given of the Violaceae occurring in Michigan, together with a key for their determination. One species of Cubelium and 34 of Viola are recognized in the state.-Ernst A. Bessey.

6722. TOTTEN, H. R. Wild ferns and flowers of Chapel Hill. Jour. Elisha Mitchell Sci. Soc. 38: 12. 1922.-Tradescantia virginiana L. and Silene alba Muhl. are added to the list of Chapel Hill (North Carolina) species.-W. C. Coker.

6723. TURRILL, W. B. Convolvulus nitidus Boiss., from the Balkan Peninsula. New Phytol. 22: 95-96. 1923.-The species named, known hitherto only from the mountains of southern Spain, is here reported from a similar locality (Mt. Ali-Botusch) in the Balkans.— I. F. Lewis.

6724. Voigt, ALBAN. Beiträge zur Floristik des Tessins. II. [Contributions to the flora of Tessin. II.] Sitzungsber. u. Abhandl. Naturw. Ges. "Isis" 1920-21: 11-19. 1922.The author reports the results of his 1921 explorations in the southern part of the canton of Tessin, Switzerland. He describes the physiographic and geological features of the district and comments on the large number of adventive plants in the flora, many of these having been introduced with Italian hay in 1919. The rare and otherwise interesting vascular plants collected are enumerated and number 91 species, varieties, and forms, 46 of which are new to the canton. Each species is accompanied by data regarding localities, and a few descripive or distributional notes are given. A new variety, Stachys Ocymastrum var. purpureiflorus Thell., and a new form, Sisymbrium Loeselii f. pallidiflorum Voigt, are described. A. W. Evans.

6725. WIINSTEDT, K. Farve-Vaid (Isatis tinctoria L.) vildtvoksende i Danmark. [Isatis tinctoria naturally growing in Denmark.] Nat. Verden 6: 33-36. 1922.-Isatis tinctoria L. var. maritima Rupr. was found in 1919 and 1920 on the island of Bornholm in the Baltic, where it was discovered in 1861, although absent in the meantime. It appears to have come from the Swedish coast where it grows spontaneously. The seed float on salt water 4-6 days. The plant was never much cultivated in Denmark, the localities are very few, and the occurence may always be connected with import of foreign grass seed.—Ernst Gram.

6726. YUNCKER, T. G. The genus Cuscuta in Michigan. Papers Michigan Acad. Sci. 1: 185-189. 1923.-A list is given with key of the 8 species of Cuscuta occurring in Michigan, based upon specimens examined by the author.-Ernst A. Bessey.

MISCELLANEOUS, UNCLASSIFIED PUBLICATIONS

B. E. LIVINGSTON, Editor

S. F. TRELEASE, Assistant Editor

6727. AMANN, J. L'étude der mousses au microscope polarisant. [The study of mosses by means of a polarizing microscope.] Rev. Bryologique 50: 6-9. 1923.-The author presents some of the results obtained by the use of a polarizing microscope in the study of the leaves, peristomes, and other parts of mosses. He distinguishes between positive and negative effects, and brings out the fact that the optical properties of the cell-membranes depend upon chemical composition.-A. W. Evans.

6728. BADE, E. Between two worlds. Sci. Amer. 128: 34. 4 fig. 1923.-This article points out the various difficulties encountered in attempting to differentiate lower plants and lower animals, when employing the criteria of function and behavior.-Chas. H. Otis.

6729. BAILEY, VERNON. Sources of water supply for desert animals. Sci. Monthly 17: 66-86. 1923.-Some rabbits eat the prickley pear, Opuntia Engelmanni, and parts of even more spiny cacti. Talinum is also used. Rats, gophers, ground squirrels, and grasshopper

mice may use very little or no water, except that obtained from plants. Even man may live with a small amount, if he knows the plants to use and becomes accustomed to the conditions. -L. Pace.

6730. EWART, ALFRED J. Biology during the war and after. Rept. Australasian Assoc. Adv. Sci. 15: 134-144. 1921.-This is the President's address before Section D of Australasian Association for the Advancement of Science. It contains a short address on the value of botany as a science, followed by reports of recent Australasian researches in botany and zoology and by a short review of the work done at the National Herbarium of Victoria during the past 15 years.-Ray C. Friesner.

6731. FERRIS, G. F. The place of the systematist in modern biology. Sci. Monthly 16: 514-520. 1923.-The work of the systematist is not only for his own field; all other biologists depend on it. It should have the best minds, and not be left for amateurs.-L. Pace.

6732. GREER, W. C. Black gold of the Tropics. Pharm. Era 56: 215-218. 2 fig. 1923.A description is given of the processes through which rubber passes in the manufacture of various articles.-C. M. Sterling.

6733. KÖHLER, A. Das Mikroskop und seine Anwendung. [The microscope and its uses.] Abt. 11. Physikalische Methoden. Heft 2. Lieferung 95 of the Handbuch der biologischen Arbeitsmethoden. [Vol. II. Physical methods. Heft 2. Part 95 of the Handbook of biological laboratory methods.] P. 171-352. Fig. 138-248. Urban and Schwarzenberg: Berlin and Vienna, 1923. Edited by EMIL ABDERHALDEN.-The subject is treated under the following heads: geometrical relation between object and image; application of the law of images to lenses of definite thickness, or to a system of such lenses; remarks on photometry; photometrical relation between object and image; loss of light in optical systems; remarks concerning seeing with the unaided eye. Pages 237-286 are devoted to the hand lens, with the following sections: the formation of a level field through the magnifier; the imaging of a body through the magnifier; the imaging of an illuminated transparent or reflecting preparation; image defects of the magnifier and their improvement; different forms of magnifiers. Pages 286-352 deal with the simple microscope, with sections as follows: the imaging of a plane object by the simple microscope; the imaging of illuminated transparent objects; image defects of simple microscopes and their improvement; a few forms of the simple microscope; mountings and stands of the simple microscope; testing the magnifier and the simple microscope and measuring the magnification.-C. S. Gager.

6734. MANGHAM, SIDNEY. Laboratory Notes. A simple respiroscope. A cheap bench light. New Phytol. 21: 230-231. 1922.

6735. MAWSON, DOUGLAS. Australasian Antartic expedition. Report on progress of publication of scientific results. Rept. Australasian Assoc. Adv. Sci. 15: 286-291. 1921.

6736. NORMAN, J. R. Methods and technique of reconstruction. Jour. Roy. Microsc. Soc. London 1923:37-56. 8 fig. 1923.-A method of reconstructing objects in wax from serial sections is described.-R. E. Cleland.

6737. SLOSSON, EDWIN E. Current comment. Sci. Monthly 16: 557. 1923.-Power in large quantities may be obtained from the fruit of prickly pears.-L. Pace.

While BOTANICAL ABSTRACTS is covering much of the world's plant literature, many serial publications remain to be cared for. Additional Collaborators are therefore necessary if the journal is to attain approximate completeness. Workers, not now Collaborators, who are interested in contributing abstracts, should communicate with the Chairman of the Bibliography Committee (J. R. Schramm), National Research Council, Washington, D. C., U. S. A.

Most of the abstracting for BOTANICAL ABSTRACTS is arranged for by the Bibliography Committee, which assigns to individual Collaborators in all parts of the world the complete responsibility for furnishing the abstracts of all material, within the scope of Botanical Abstracts, appearing in one or a limited number of specified serial publications. These assignments are adapted as nearly as possible to the Collaborators' interests, library facilities, and linguistic equipment. The Bibliography Committee maintains an accurate record of the state of the abstracting in each assigned serial publication and is thus enabled to keep the abstracting reasonably up to date.

Abstracts of non-serial literature are arranged for by the Editors of the Sections concerned. The cooperation of authors is solicited in sending abstracts, copies of their contributions, or both, to the Editor-in-Chief.

BUSINESS NOTICE

It is normally mailed from
Claims are allowed for copies

BOTANICAL ABSTRACTS is published monthly. Baltimore on or about the eighth day of the month. lost in the mails, but such claims must be made within 30 days (overseas 90 days) of date of issue. Loss of copies due to failure to notify the Business Manager of change of address does not constitute a valid claim.

Prices: Prices, postpaid, are as follows: Volumes 1 and 2 cannot be supplied. Volumes 3, 4, 5, 6, 7, 8, 9, and 10, domestic, $3; Canada, $3.12; other countries, $3.25. Volumes 11 and 12, domestic, $10; Canada, $10.40; other countries, $10.80. Single copies will not be sold except in cases where sets are already broken; price $1 each.

Orders: The Business Manager is prepared to execute all orders and the journal will be benefited if subscriptions are placed directly with him. Personal checks on local banks are accepted without discount.

Accounts: All accounts are payable strictly in advance. Notice of expiration of subscription and invoice for the new volume are sent to subscribers in ample. time to avoid interruption in receipt of numbers as issued. The entire mailing list is suspended at the end of each volume and the "active" list is made up of those subscribers from whom a remittance has been received before the first issue of the new volume goes to press. "Till forbidden" orders are always excepted. Address: All business communications should be sent to the Business Manager of BOTANICAL ABSTRACTS, College of Agriculture, Ithaca, New York, U. S. A. Checks should be made payable to "BOTANICAL ABSTRACTS."

The Business Manager will pay publishers' price for volumes 1 and 2.