The officers for the current term are the following: President: Theo. Hough. Vice-President: A. L. Lamb. Secretary: H. M. Brune. Executive Committee: Langdon Williams, Chairman; C. E. Coates, Theo. Hough, H. O. Thompson, Allan C. Woods.

The meetings are held at the rooms of the Matriculate Society, 111 W. Monument street, at 8 p. m., on alternate Mondays.

LOAN EXHIBITION OF DRAWINGS, ETC.

By the liberality of A. L. Frothingham, Esq., a large number of original drawings by early Italian masters, chiefly of Bologna, and some interesting marble fragments, bought from the Campana collection, were placed on exhibition in the rooms at 106 Monument street. Some other interesting archæological relics have also been exhibited in the same house. This will be followed by periodical exhibitions of engravings, photographs and antiquities. The arrangements are under the auspices of the Archæological Society of the University. (See p. 28 of this Circular). The rooms are open Saturdays from 2 p. m., till dark.

The autumn meeting of the American Oriental Society (Prof. W. D. Whitney, President; Prof. C. R. Lanman, Secretary), was held in Hopkins Hall, Wednesday and Thursday, October 29, 30.

The annual session of the American Academy of Medicine (Dr. Benjamin Lee, President) was held in Hopkins Hall, Tuesday and Wednesday, October 28, 29.

The graduate students and their friends were invited to a reception in the Biological Laboratory, Monday evening, December 1, 1884.

NOTE RESPECTING THE EXCURSION MAP OF BALTIMORE, PUBLISHED BY THE JOHNS HOPKINS UNIVERSITY.

This map of Baltimore and its vicinity is intended primarily for the convenience of members of the Johns Hopkins University Field Club and such other students as may be desirous of investigating the natural history or exploring the natural beauties of this neighborhood. It is hoped that it will also prove a useful guide to other citizens of Baltimore whose walks or drives may lead them into the adjoining country.

The map is not to be regarded as complete or final in any respect, but only as the first step toward the attainment of a really good representation of the region. In the preparation of this first edition there has been no fresh survey; only the data already published have been compiled. These materials are more or less defective or inaccurate, and it is earnestly requested that all persons using the map, whether members of the University or not, make suggestions as to its improvement. It is proposed to publish new editions from time to time, upon which it is very desirable to embody all available new information or corrections concerning roads, paths, accurately determined elevations, important local names, etc., etc. Such information, as well as suggestions relative to the improvement of the general character of the map, are therefore solicited and may be sent in writing, with a signature, to the Field Club, at the office of the Johns Hopkins University.

For the purpose of additional convenience in its use the map has been ruled into squares of one mile each, the lines being lettered at the top and bottom and numbered at the sides for easy reference. Time tables of such lines of street cars as run from the city for a considerable distance into the country may be found in the Baltimore Directory.

A few copies of the map are for sale at Messrs. Cushings & Bailey, Messrs. J. Murphy & Co., and at the University. Price, $1.00.

ANNOUNCEMENT OF PUBLICATION.

By invitation of the Johns Hopkins University, SIR WILLIAM THOMSON, LL. D., F. R. S. L. and E., Professor of Natural Philosophy in the University of Glasgow, Scotland, gave a course of eighteen lectures, on Molecular Dynamics, before the physicists of the University, in October, 1884.

Stenographic notes were taken by Mr. A. S. Hathaway, B. S., Cornell University, lately a Mathematical Fellow of the Johns Hopkins University, and these notes (with additions subsequently made by the lecturer) have been carefully reproduced by the Papyrograph Plate Process. A bibliography of the subjects considered will also be given with the lectures. In all there will be about 350 pages, quarto.

A few copies are offered for sale at $5.00 net. The edition is strictly limited to 300 copies, and orders should therefore be sent at once to the Publication Agency of the Johns Hopkins University, Baltimore, Md., U. S. A. Copies may also be procured from Messrs. Mayer & Müller, W. Französische Strasse 38, Berlin; A. Hermann, 8 Rue de la Sorbonne, Paris; Trübner & Co., 57 Ludgate Hill, London.

The following notice of the lectures is reprinted from Science, November 7, 1884:

The title 'Molecular dynamics' does not give an accurate idea of the nature of Sir William Thomson's recent course of lectures at the Johns Hopkins university. The object of the lectures was to consider the possibility of placing the wave-theory of light upon a perfectly tangible physical basis which should be sufficient to account for all the phenomena. The lecturer stated at the outset that he would be occupied more with pointing out difficulties than with removing them. He expressed the conviction that what takes place in the propagation of light-at least through gases, if not through solids and liquids-can be represented in its essential features by supposing a mass of vastly denser matter in the ether, bounded by a perfectly rigid shell; this shell surrounded at a small interval by another perfectly rigid spherical shell; and so on.

as

Each shell is connected with the one outside it by a number of spiral springs: the precise number of the shells is not a vital matter in the theory, and the actual number may be infinite, i.e., the system of shells may constitute a continuous atmosphere to the molecule. The problem of the modes of vibration of this system is essentially the same that of a system of particles connected by springs in a straight line. As for the ether itself, it is to be considered as a substance which may not be an elastic solid, but which, so far as the luminiferous vibrations are concerned, moves as if it were an elastic solid. The lecturer carried on the mathematical discussion of these two dynamical problemsthe propagation of waves in an elastic solid, and the motion of a system of spring-connected particles in a straight line-side by side, usually devoting the first half of a lecture to one problem, and the remainder to the other.

It is impossible here to give any specific account of the contents of the lectures; it may be stated, however, that many of the cardinal phenomena of light were shown to be explicable by the hypothesis sketched above, but that the phenomenon of double refraction presented apparently insuperable difficulties, as it has done in all previous attempts to explain it. By proper suppositions regarding the elasticity of the springs (in the mechanical 'model' of the phenomenon given above) double refraction would indeed be produced; but its law would be widely different from that actually observed.

The lecturer was conversational in his manner, made almost no use of notes, and was full of enthusiasm for his subject. The audience was composed of professors of physics from eastern and western colleges, scientific men from Washington, and students and instructors of the Johns Hopkins university. The lectures, while not condensed in form, presupposed thorough familiarity with the physical and mathematical theories involved. A verbatim report of them, from stenographic notes, will be issued in a limited edition, by the use of the papyrograph process. At the close of the course, Sir William Thomson was presented by the class with one of Rowland's concave gratings, as a memento of their connection with him.

28

Scientific Association.

November 5.-Fifty-ninth regular meeting. Professor Martin in the chair. Fifty-one persons present.

Officers were elected for the ensuing year as follows:

Professor Martin, President; Professor Rowland, Vice-President; Dr. E. H. Keiser, Secretary; Committee on Papers, Professor Martin, Dr. Franklin, Mr. G. A. Liebig, Jr., Dr. Keiser, Dr. Brooks, and Mr. W. Noyes.

Papers read:

On Sir William Thomson's models to illustrate the theory of light, by H. A. ROWLAND.
On a New Theory of Variation, by W. K. BROOKS. (Abstract on p. 14).
Recent Experiments on the Sense of Rhythm, by G. S. HALL.

Philological Association.

October 10. Fifty-sixth regular meeting. Professor Gildersleeve in the chair. Thirtytwo members present.

Papers read:

On a Philological Expedition to Canada. by A. M. ELLIOTT. (Abstract on p. 20).
On the Meaning of Baalim and Ashtaroth in the Old Testament, by A. L. FROTHING-
HAM, JR.

November 7.-Fifty-seventh regular meeting. Professor Gildersleeve in the chair.
Thirty-nine members present.

Papers read:

On Petrarca's relations to the Universities of his time, by A. EMERSON.
Two Etymological Notes, by M. BLOOMFIELD.

Some Account of Belock's Speculation on the Financial History of Athens, by C. D.
MORRIS.

On Weil's View of the Origin of the Word "Poet," by B. L. GILDERSLEEVE.

Historical and Political Science Association.

October 3.-Dr. H. B. Adams in the chair.

Pullman, a Social Study, by R. T. ELY. (To be published in Harper's Monthly.) The American Historical Association, by H. B. ADAMS.

October 10.-Dr. H. B. Adams in the chair.

Pennsylvania State Finance and Taxation, by T. K. WORTHINGTON.

Sources of information for the study of Slavery, by GENERAL WILLIAM BIRNEY. October 17.-Dr. H. B. Adams in the chair.

The House of Representatives, Revenue and Supply, by WOODROW WILSON. Review of Shaw's "Icaria," by D. R. DEWEY.

October 24.-Dr. H. B. Adams in the chair.

Review of the seventh volume of the U. S. Census on "Valuation," by JOHN C. ROSE. (Abstract published in The Nation, October 30, 1884).

The Progress of Civil Service Reform in the United States, by H. B. ADAMS. October 31.-Dr. H. B. Adams in the chair.

Land Laws of Mining Districts, by CHARLES HOWARD SHINN, (Published in full in the "Historical Studies," Second Series, XII, December, 1884).

The Government and Civil Service of China, by DR. MCCARTHY, for many years a resident in China.

November 7.-Dr. H. B. Adams in the chair.

History of Witchcraft in Connecticut, by C. H. LEVERMORE.

The House of Lords, by E. R. L. GOULD.

November 14.-Dr. H. B. Adams in the chair.

City Government in Baltimore, by JOHN C. ROSE.

The proposed Revision of the City Charter of Boston, by H. B. ADAMS.

Archæological Society.

On November 19, the Archæological Society of the University held its opening meeting at 106 W. Monument street, where the rooms of the Society are now established. MR. M. COHEN read a paper on Col. M. I. Cohen, who made the valuable collection of Egyptian antiquities recently acquired by the University. (See p. 21.) A communication was made by PROFESSOR HAUPT on some remarkable early Chaldean antiquities lately purchased by Prof. A. Marquand, of Princeton.

DR. FROTHINGHAM spoke on some Arabian and other antiquities belonging to the same collection.

DR. EMERSON called the attention of the Society to some interesting late works on the history of Greek Art.

PROF. HARRIS presented the photograph of the first lines of the "Teaching of the Twelve Apostles," proving it to be in the same hand as the preceding part of the MS. On Saturday, November 22, there was opened at 106 Monument street, under the direction of the Archaeological Society, an exhibition of original drawings, in red chalk, pen and ink, water colors and pencil, by old Italian masters, loaned from the collection of A. L. Frothingham, which was purchased by him in 1870 from the heirs of Prof. Angelini, of the Academy of Fine Arts of Bologna. There are 85 drawings, of which 52 are by masters of the School of Bologna, extending over the period from Prospero Fontana (1512–1597), the precursor of the Caracci, who were the regenerators of the School, down to Gaetano Gandolfi (1734-1802), the last of the imitators of the Caracci. Besides the Caracci (Lodovico, Agostino and Annibale), it includes good examples of Guido Reni, Guercino, Franceschini, and Donato Creti.

The Roman School is represented by 14 examples, including Sodoma of Sienna (1479-1554), Pellegrino Tibaldi, the imitator of Michel Angelo, and the Scholars of

[No. 35.

Raphael, Polidoro da Caravaggio and Julio Romano: from Naples is a pen drawing by Josef Ribera, "Il Spagnoletto."

Of the schools of North Italy are notable drawings by Leonardo da Vinci of Milan (1452-1519), Correggio of Parma (1494–1534), Andrea Mantegna of Padua (1430–1506), Giorgione of Venice (1478-1511). There is an interesting example of Henricus Goltzius (1558-1617), who, though not a native, studied in Italy and was a true child of the Italian Renaissance.

A number of fragments of Roman and Pompeian sculptures from the same collection were also on exhibition. They form a part of some acquired in 1871 at Rome at the sale of the remnant of the famous collection of the Marquis Campana. Most of the pieces are fragments of sarcophagi belonging to the second and third centuries after Christ. Some are heads which adorned the corners of the lids, some are narrow reliefs from the front of these lids, while the greater portion belonged to the lower part of the sarcophagus.

Metaphysical Club.

November 18.-Thirty-ninth regular meeting. Professor Hall in the chair. Nineteen members present.

It was decided to discontinue the existing Metaphysical Club and after proceeding tentatively for a few meetings, to effect an organization which shall better satisfy the needs of those interested in this department.

Reports of readings were made:

On Fred. Kapp's Grundriss einer Philosophie der Technik and on du Prel's Philosophie der Mystik, by G. S. MORRIS.

On "The Magnet" a fourteenth century manuscript of Petrus Peregrinus, by C, S. PEIRCE.

On a series of Books on Ultra-Longevity, by J. JASTROW.

On Meynert's Psychiatrie, Radestock's Genie u. Wahnsinn, and Sully's Psychology, by G. S. HALL.

A discussion on psychical research closed the meeting.

Baltimore Naturalists' Field Club.

October 15.-Dr. Williams in the chair. Thirteen members present.
The following officers were elected for the year:

President, Dr. G. H. Williams; Secretary, Dr. W. H. Howell; Chairman of Zoological section, Mr. Lugger; Chairman of Botanical section, Mr. Donaldson; Chairman of Geological section, Dr. Williams.

October 16.-Special meeting. Dr. Williams in the chair. Twenty-three members

present.

The new map of the region surrounding Baltimore published under the auspices of the Field Club, was exhibited and addresses in reference to it made by President Gilman, Dr. G. H. Williams, Mr. Uhler, Dr. B. W. Barton and Mr. G. L. Smith. November 19.-Regular monthly meeting. Dr. G. H. Williams in the chair. Twenty members present.

MR. NELSON read a note on the bark louse parasitic on the beech.

This louse is usually known as a coccus, but is probably an aphis. It has a peculiar brush-like appendage consisting of thin fragile white threads. These are composed of a substance allied to the wax secreted by bees and are a cellular secretion of epidermal glands, which in this insect are especially abundant on the dorsal side of the last four abdominal segments. In the coccus on the alder the secretion covers the whole of the back of the abdomen. The function of the secretion as far as known, is to keep the insect dry and warm. It is lost with the last moult and left clinging to the branches of the tree. No ant has been found near the colonies of the beech coccus. Neither oviparous females nor males were found in the beech coccus, but only winged viviparous females.

MR. DONALDSON of the Botanical section made a report of the field work for the past month and gave the plan of work to be adopted during the present year.

MR. MCMURRICH addressed the club on the methods of collecting and studying parasitic fungi, describing the methods to be followed in tearing out, macerating and cutting sections of specimens, and the method of innoculation experiments. MR. C. S. PALMER reported the mineralogical work of the Geological section of the Field Club.

Brown tourmaline in good crystals and tremolite in fibrous masses had been recently found in the crystalline limestone of Texas, Balto. Co. The anthophyllite-like mineral occurring at the Mt. Washington copper mine had been chemically examined by Messrs. Palmer and Kastle, who found that it agreed with anthophyllite in containing no lime, although a very considerable amount of alumina was present. The optical properties of this mineral, as determined by Dr. Williams, are those of the monoclinic system; it appears therefore to be what Des Cloizeaux has called amphibole-anthophyllite.

American Institute of Archæology, Baltimore Branch.

A meeting of the Baltimore Branch of the Archæological Institute of America, was held November 17, at 106 W. Monument Street, By grouping around Baltimore the members of several States besides Maryland, a total membership of about fifty was reached, which entitled the branch to be represented by two members at the General Council of the Institute.

It was decided that Mr. McCoy's gift to the society of one hundred dollars should be given in the form of a life-membership in the Institute to whomever, being a resident in Baltimore, should present an archæological dissertation judged worthy of the prize. Professors Gildersleeve, Warren and Elliott were appointed a committee to arrange the details of the above proposal. Finally the secretaries, Drs. Emerson and Frothingham, were chosen members of the Council, which met in New York on November 20.

[Issued December 5, 1884.]

JOHNS HOPKINS UNIVERSITY.

Opened for Instruction in 1876.

The Johns Hopkins University was founded by the munificence of a citizen of Baltimore, Johns Hopkins, who bequeathed the most of his large estate for the establishment of a University and a Hospital. It was intended that these institutions should coöperate in the promotion of medical education. The Hospital buildings are approaching completion.

The foundation of the University is a capital, in land and stocks, estimated in value at more than $3,000,000; the capital of the Hospital is not less in amount.

The University was incorporated under the laws of the State of Maryland, August 24, 1867. Power to confer degrees was granted by the Legislature in 1876.

Suitable buildings have been provided in Baltimore at the corner of Howard and Little Ross Sts., and are furnished with the necessary apparatus and books.

ACADEMIC STAFF, 1884-5.

DANIEL C. GILMAN, LL. D., President of the University.
J. J. SYLVESTER, F. R. S., D. C. L., Professor (Emeritus) of
Mathematics.

BASIL L. GILDERSLEEVE, PH. D., LL. D., Professor of Greek. G. STANLEY HALL, PH. D., Professor of Psychology and Pedagogics.

PAUL HAUPT, PH. D., Professor of the Shemitic Languages.
H. NEWELL MARTIN, DR. SC., A. M., Professor of Biology and
Director of the Biological Laboratory.

CHARLES D. MORRIS, A. M., Collegiate Professor of Latin and
Greek.

SIMON NEWCOMB, LL. D., Professor of Mathematics and As

tronomy.

IRA REMSEN, M. D., PH. D., Professor of Chemistry and Director of the Chemical Laboratory.

HENRY A. ROWLAND, PII. D., Professor of Physics and Director of the Physical Laboratory.

WILLIAM H. WELCH, M. D., Professor of Pathology.
JOHN S. BILLINGS, M. D., Lecturer on Hygiene.

HIRAM CORSON, A. M, LL. D., Lecturer on English Literature.
EDMUND GOSSE, Lecturer on English Literature.

GEORGE S. MORRIS, A. M., PH. D., Lecturer on the History of Philosophy.

LÉONCE RABILLON, BACH. ÈS LETT., Lecturer on French Lileralure.

WILLIAM THOMSON, LL. D., Lecturer on Molecular Dynamics. HERBERT B. ADAMS, PH. D., Associate Professor of History. MAURICE BLOOMFIELD, PH. D., Associate Professor of Sanskrit. WILLIAM K. BROOKS, PH. D., Associate Professor of Morphology and Director of the Chesapeake Zoological Laboratory. THOMAS CRAIG, PH. D., Associate Professor of Applied Mathe

matics.

A. MARSHALL ELLIOTT, A. M., Associate Professor of Romance Languages.

J. RENDEL HARRIS, A. M., Associate Professor of New Testament Greek and Palaeography.

HARMON N. MORSE, PH. D., Associa'e Professor of Chemistry and Sub-Director of the Chemical Laboratory.

WILLIAM E. STORY, PH. D., Associate Professor of Mathematics. MINTON WARREN, PH. D., Associate Professor of Latin. WILLIAM HAND BROWNE, M. D., Librarian and Associate in English.

WILLIAM T. COUNCILMAN, M D., Associate in Pathology.
RICHARD T. ELY, PH. D., Ássociate in Political Economy,
FABIAN FRANKLIN, PH, D., Associate in Mathematics.
EDWARD M. HARTWELL, M. D., PH. D., Associate in Physical
Training and Director of the Gymnasium.

J. FRANKLIN JAMESON, PH.D., Associate in History.
ARTHUR L. KIMBALL, PH. D., Associate in Physics.
PHILIP R. UHLER, Assoriate in Natural History.
GEORGE H. WILLIAMS, PH. D., Associate in Mineralogy.
HENRY WOOD, PH. D., Associate in German.
CHARLES F. RADDATZ, Examiner in German.
HUGH NEWELL, Instructor in Drawing.
EDWARD H. SPIEKER, PH. D., Instructor in Latin and Greek.
HENRY A. TODD, A. B., Instructor in Romance Languages.
CHARLES L. WOODWORTH, JR., Instructor in Elocution,
ALFRED EMERSON, PII. D., Instructor in Classical Archæology.
GEORGE HEMPL, A. B., Assistant in German,
WILLIAM H. HOWELL, PH. D., Assis'ant in Biology.
EDWARD H. KEISER, PH. D., Assistant in Chemistry.
CHARLES A. PERKINS. PH. D., Assistant in Physics.

OTTO LUGGER, Curator of the Biological Museum

PLAN OF THE CIRCULARS. The Johns Hopkins University Circulars are published at convenient intervals during the academic year for the purpose of communicating intelligence to the various members of the University in respect to work which is here in progress, as well as for the purpose of promulgating official announcements from the governing and teaching bodies. During the current academic year, successive circulars may be expected in the months of November, December, January, February, March, April, May, and June, to be followed at the close of the year by an index.

Although these circulars are designed for the members of the University, they have frequently been called for by institutions and libraries at a distance, and also by individuals who are interested in the literary and scientific activity of this University. Sul scriptions and exchanges are therefore received.

TERMS OF SUBSCRIPTION.

For the current year, 1884-5, $1. For the year 1883-4, (140 pp. in cloth covers), $1.50.

$3.

For the year 1882-3, (156 pp. in cloth covers),

For the years 1880-2, (250 pp. in cloth covers), $5. Subscribers to the Circulars will also receive the Annual Register and Report of the University. All subscriptions should be addressed to the "Publication Agency of the Johns Hopkins University."

Communications for the Circulars should be sent in prior to the first day of the month in which they are expected to appear.

PUBLIC LECTURES.

Notice in Respect to the Admission of the Public. In answer to inquiries, and in correction of some current misapprehensions, the following statements are made in respect to the public lectures given in the Johns Hopkins University.

These courses are academic lectures, designed primarily for the members of the University, and supplementary to the regular class-room work of the students.

As the members of the University rarely require the entire room, the Trustees have taken great pleasure in inviting other persons, not connected with the University, to attend.

As these lectures are not intended for popular entertainment, but for the instruction of students, those persons first receive tickets, in most cases, who are known to be especially interested in a particular course,-ladies as well as gentlemen.

There is no general course ticket issued. Applications should state specifically the course for which tickets are desired. Programmes and other current information pertinent to university work may be found in the University Circulars, sent to subscribers on the payment of one dollar per annum, by the Publication Agency of the University.

The usage of giving personal notification has been discontinued, and those therefore who are interested in such announcements should hereafter consult the Circulars.

It will save much delay if applications for tickets and inquiries on these and other routine matters are addressed not to individuals but to the JOHNS HOPKINS UNIVERSITY, by postal card, and answers will be promptly returned by mail. Personal applications consume time needlessly.

The lectures begin at 5 o'clock punctually. The doors of the hall are opened at fifteen minutes before 5, and the lectures do not exceed an hour in the delivery.

PUBLICATIONS ISSUED UNDER THE
AUSPICES OF THE UNIVERSITY.
I. American Journal of Mathematics.

The publication of this journal commenced in 1878, under the editorial direction of Professor Sylvester, and is now conducted by Professor Simon Newcomb as Editor, and Dr. T. Craig as Associate Editor. Six volumes of about 400 pages each have been issued, and the seventh is in progress. It appears quarterly, in the quarto form. Subscription $5 per year. Single numbers $1.50.

II. American Chemical Journal. This journal was commenced in 1879, with Professor Remsen as editor. Five volumes of about 450 pages each have been issued, and the sixth is in progress. It appears bi-monthly. Subscription $3 per year. Single numbers 50 cts.

III. American Journal of Philology.

The publication of this journal commenced in 1880, under the editorial direction of Professor Gildersleeve. Four volumes of about 570 pages each have been issued, and the fifth is in progress. It appears four times yearly. Subscription $3 per volume. Single numbers $1.00.

IV. Studies from the Biological
Laboratory.

[Including the Chesapeake Zoological Laboratory.] The publication of these papers commenced in 1879, under the direction of Professor Martin, with the assistance of Dr. W. K. Brooks. Two volumes of about 500 pages, octavo. and 40 plates each, have been issued, and the third is in progress. V. Studies in Historical and Political Science.

The publication of these papers was begun in 1882, under the editorial direction of Dr. H. B. Adams. A first series of 470 pages and a second of 630 pages are now completed and a third series is in progress. Subscription $3 per volume.

The following publications are also issued by the University:

The UNIVERSITY CIRCULARS. Subscription $1 per year.

The ANNUAL REPORT presented by the President to the Board of Trustees reviewing the operations of the University during the past academic year.

The ANNUAL REGISTER giving the list of officers and students and stating the regulations of the University. Published at the close of the academic year.

The University Circulars, Annual Report, and Annual Register will be sent by mail for one dollar per annum.

All communications in respect to these publications should be addressed to the Publication Agency of the Johns Hopkins University," Bultimore, Maryland.

In addition to the serials above named, a few copies are for sale of the papers named below:

STUDIES IN LOGIC. By members of the Johns Hopkins University. C. S. Peirce, Editor. (Boston: Little, Brown & Co.) 1883. 123 pp., 120. $2.

THE DEVELOPMENT AND PROPAGATION OF THE OYSTER IN MARYLAND By W. K. Brooks. 1884. 193 pp., 40. 13 plates and 3 maps. $5.

ON THE MECHANICAL EQUIVALENT OF HEAT. By H. A. Rowland. 1880. 127 pp., 8o. $1.50.

NEW TESTAMENT AUTOGRAPHS. By J. Rendel Harris. 1882. 54 pp., 8o. 4 plates. 50 cents.

SIR WILLIAM THOMSON'S LECTURES ON MOLECULAR DYNAMICS. Delivered at the Johns Hopkins University in October, 1884. Reproduced from stenographic notes by the papyrograph plate process. 370 pp., 4to. $5.00.

SCIENTIFIC ASSOCIATION.

What is the Explanation of Acquired Immunity from Infectious Diseases? By GEORGE M. STERNBERG, Surgeon, U. S. A.

[Abstract of a paper read before the University Scientific Association, December 3, 1884]. Three explanations have been offered, viz:

(a) The "exhaustion theory" proposed by Pasteur (Comptes rendus Acad. des Sc., XC. pp. 952-958), which supposes that some substance present in the body of a susceptible individual up to the time of a first attack, and which is essential for the development of the specific germ of the disease, is exhausted during the attack, and that consequently this particular germ is unable subsequently to multiply in the body of this individual.

(b) The "antidote theory" which supposes that some chemical substance is produced during the attack which is inimical to the development of the germ, and which, remaining in the body of the individual, prevents its subsequent invasion by the same microbe. (This theory has been advocated by Paul Bert, by Klebs, and recently by Klein in his Micro-organisms and Disease. (The Practitioner, London, October, 1884, p. 248).

(e) The "vital resistance theory," which supposes that immunity is due to an acquired tolerance on the part of the living cellular elements of the body to the poisonous products produced by disease germs-to which they probably owe their specific pathogenic power—and a consequent ability to resist invasion by these germs. According to this view individual and race differences in susceptibility, as well as the more or less perfect immunity resulting from a single attack of any one of the specific infectious diseases, are phenomena depending upon differences in vital resisting power, either inherited or acquired. (This view was supported by the present writer in a paper published in the Am. Journal of the Medical Sciences of April 1st, 1881, and by Grawitz in a paper published in Virchow's Archiv, on the 8th day of April, 1881. It has also been ably advocated by Salmon in this country.)

The first explanation (a) is untenable for the following reasons:

Our credulity is overtaxed by the supposition that various chemical substances, of no special use in the animal economy, but essential for the development of the specific disease germs, are stored up in the blood and tissues from birth until the date of attack, in spite of the ample provision made for the excretion of useless or noxious products; that these several substances are exhausted only by the development of particular disease germs—i. e., one substance by the germ of small-pox, one by that of measles, etc., etc.;-that these substances are formed and stored up in the body for no other apparent purpose than to serve as pabulum for various disease germs; and that having served this purpose they are not reformed, after recovery, by a continuance of the same physiological processes to which their origin must have been due in the first instance.

The protection resulting from inoculations with "attenuated virus" is also opposed to this view; for it is impossible to believe, for example, that the pabulum which would have nourished the small-pox germ in sufficient numbers to produce a malignant case of small-pox is exhausted by vaccination. Finally, we have experimental evidence that the theory is not correct. Salmon has shown that the flesh of a fowl which has immunity from fowl cholera, as a result of inoculation with attenuated virus, when made into bouillon, furnishes a good culture-medium for the microbe of this disease. And Klein states that "when of the tissues of a guinea-pig, or mouse, or rabbit, dead of anthrax, an infusion is made, and this is used as nourishing material for bacillus anthracis in artificial cultures, it is found that these latter thrive splendidly." (The Practitioner, London, October, 1884, p. 248). The "antidote theory" is equally untenable and for similar reasons. It is difficult to believe that when we vaccinate an infant a chemical substance is formed, and stored up in the tissues in spite of the changes due to physiological processes constantly going on in the body, in sufficient quantity to prevent the development of the small-pox germ for years, and perhaps during the lifetime of the individual.

Moreover, this theory requires us to admit that there is a special antidote for each specific disease germ; that each disease germ produces its own antidote; and that one or several of these peculiar chemical subtances stored

up in the body of an individual does not prevent the development of other disease germs. Whereas all of those chemical substances which have been proved by laboratory experiments to prevent the development of germs— e. g., iodine or mercuric chloride-are antidotes for all known organisms of the class to which disease germs belong, although not always in the same

amounts.

Finally the experimental evidence referred to as opposed to the exhaustion theory is equally fatal to the antidote theory. For, if the micrococcus of fowl cholera, or the bacillus of anthrax are prevented from multiplying in the blood and tissues of an immune animal by the presence of a chemical substance inimical to their development, then this substance should also prevent the development of these microbes in blood drawn from the vessels of such an immune animal, or in an infusion made from its flesh. Whereas the experiments of Salmon and of Klein above referred to, show that this is not the case. We must therefore reject this theory as untenable.

The "vital resistance theory" as above formulated, is supported by numerous facts and arguments drawn from analogy, which may be briefly stated as follows:

There is great difference in individual susceptibility to first attacks, and in the degree of immunity conferred by a single attack. Some individuals resist repeated exposure under the most trying circumstances, while others suffer an attack from the slightest possible exposure.

Individual susceptibility also varies greatly at different times and is increased by depressing influences, such as fatigue, fear, inanition, inebriation, hemorrhage, chronic wasting diseases, etc.

Unusual resisting power may be overcome by exceptionally large doses of the infectious material, and this is true, to some extent at least, of acquired immunity as well as of inherited insusceptibility.

Second attacks of the infectious diseases not infrequently occur, and these are sometimes fatal. In other words, immunity is not absolute but relative.

We have also examples of relative race immunity, as, for example, in the relative insusceptibility of the negro to yellow fever and to the effects of the malarial poison, and in the immunity of Algerian sheep from anthrax. This race immunity is doubtless due to a tolerance established by natural selection in races exposed for many generations to the continuous action of these poisons.

On the other hand infectious diseases are exceptionally malignant when first introduced among a virgin population.

Physicians are familiar with numerous examples of acquired tolerance to toxic agents-e. g., to opium, tobacco, arsenic, etc.

We know that living tissues and blood within the veins of a living animal resist the invasion of putrefactive organisms; whereas a severed limb, or blood drawn from the vessels into a test tube quickly undergoes putrefaction. This may serve as an example of vital resistance to invasion by microorganisms of the same class to which disease germs belong.

The tolerance, or increased vital resistance, which according to this hypothesis is acquired by the living cellular elements of the body, during an attack of one of the infectious diseases, to the toxic agent which gives the germ its specific pathogenic power, must be transmitted through successive generations of cells-nerve cells, gland cells, epithelium cells, leucocytes, etc., -in order to explain continued immunity, inasmuch as the cellular elements of the body are constantly undergoing destruction and are as constantly replaced by their cellular progeny. Biologists will have no difficulty in supposing that this is the case, and that under the influence of the laws which govern the hereditary transmission of acquired properties from cell to cell, the tolerance acquired during an attack has a more or less permanent character. Numerous examples might be given in support of this view.

Acquired characters are not, however, as a rule, transmitted through the sperm cell or germ cell to the offspring of the individual. Our explanation is therefore not opposed by the fact that the children of an immune individual do not inherit immunity. As already stated race immunity results rather from continued action of the laws of natural selection and survival of the least susceptible from birth-an inherited insusceptibility which is transmitted to the offspring.