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another phenomenon that has been sometimes gently bending the tongues and pens of our physical theorists towards the profound language, that procured veneration to occult causes fome centuries ago. It is the doctrine of M. de Buffon, whose genius is of the comprehensive and combining kind, that the laws of affinities are the same with that general law by which the celeftial bodies act upon each other, and that they (affinities) exert their powers in the same proportions of masses and distances. Sage, in the year 1773, composed a table of affinities upon this principle of gravity; but a farther observation of M. de Buffon, if it be true, renders this principle inadequate to the phenomena, and consequently uncertain and ambiguous: the observation is; that figure, which in the celestial bodies has little or no influence on the law of their action on each other, because their distance from each other is great, has an extensive influence, and does almost all, in the affinities between bodies, whose distance from each other is small or null. Now this observation disconcerts the hypothesis of specific gravity; for if the degrees of affinities depend absolutely upon the figure of the constituent parts of bodies, these degrees mult, like the figures, vary ad infinitum, even where the specific gravities are the same. The different operations of different falts on various substances, and the different crystallizations, that are obvious to the eye of an attentive observer, will not permit our Author to call in question this obfervation of M. de Buffon. He affirms, nevertheless, that our perfect ignorance of the figure of the constituent parts of bodies, which the philosopher of Paris has been so gracious as to acknowledge, obliges us, in our enquiries after the causes of particular afinities, to confine our researches to the different proportions and relations which take place between the specific gravities of the particular substances. That is to say-we do not know the true cause, and therefore must take up with such a cause as we can come at.

Simple affinity is the tendency of two homogeneous bodies to mutual union and cohesion, and the more that the substances are homogeneous, the more powerful is the cohesion or attraction; nor, according to our Author, can there be any affinity between two heterogeneous substances, unless a third substance intervene; which has something analogous 'to, or in common with, them both. It is thus that oil and water may be united by the intervention of an alkali:--It is true, continues our Author, that we frequently see substances, that do not appear to us at all homogeneous, blended together, with ease, in the most perfect union; but, on close inquiry, it will be found, adds he; that these substances have some parts that are analogous to each other, and even homogeneous, though in all their other parts they are heterogeneous in the highest degree. Such are the APP. Rev. Vol. lx, Nn

di folvents disolvents and chymical menstruums, which act palpably on fübstances with which they seem to have no analogy; but no menstruum, according to our Author, can dissolve a substance, with the principles of which it has no sort of analogy or homogeneity; and if acids act in this manner upon metals, it is because the phosphorus, which is the principle of metallism (if we may use that term), contains an acid.

Íhe relation, then, of analogy or homogeneity, that different substances have with their menftruums, and these latter with their substances, is what the Chymists more especially distinguish by the name of affinity, and the different degrees of this relation seem to be derived from the laws of gravity. Our Author therefore treats the subject of affinity, thus defined in its nature, and determined in its degree, by reducing it to two general laws, ist, the relation or analogy of different menftruums to the same substance; 2dly, the relation of different substances to the same menftruum. The detail into which our Author enters in the illustration of these laws is methodical, clear and interesting, and it occupies the first ten letters of this volume.

In the eleventh and twelfth he treats of aeriform substances, which are known, at present, under the denomination of gas. We find under this article, the relation of a fact, which proves, in a very striking manner, the anti-leptic quality of fixed air or the mephitic acid. At Latera (says our Author), near Bolsena in Italy, a goat which had died in the vapour of a non-inflammable moffet, was observed to remain sound and entirely exempt from putrefaction during the space of five or six months.

In the two following Letters Dr. DEMESTE treats of phosphoric and saline substances, with his usual sagacity; and then proceeds to lithology, or the history of stones. Linnæus was the first who perceived that there can be no cryftallization without a saline principle, and therefore ranged crystallized stones in the class of salts. Sage generalized ftill farther the idea of Linnæus, and being convinced by the analytic process, that all the earths and stones of which our globe is compofed, result from a combination of one or more acids with an alkaline or terreous basis, he concluded from thence that they must be real, faline mixts, though void of tafte and savour, and almost all indiffolva able in water *. M. Romé de L'Ise, by his crystallographical observations, has also confirmed this hypothesis, and shewn the analogy there is between falts and stones. Our Author adopts the division, made by M. Sage, of lithology into fix classes, but

Our Author fays almost all, -for the gypsum or plaster stone, of which there are such immense quarries, is really, notwithstanding the general opinion, susceptible of solution in a large quantity of water

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does not arrange ftony substances in these classes in the same manner with that famous mineralogist. He describes with the greatest accuracy all the crystals hitherto known; his descriptions, indeed, are not accompanied with figures, but he makes amends for this by referring the Reader to those which are to be found in the plates of M. Romé de l'Isle's excellent essay (as it is modestly called) concerning crystallography. These figures our Author points out exactly, and they are of great use in the perufal of these letters, in which the Reader will find new aspects of the proceedings of nature in this branch. Besides, the utility of these crystallogical researches will appear greater than may be imagined at first light, when it is considered, that they furnish consequences and results, which explain the formation of those rocks of the granit kind, which the most celebrated naturalists, at present, consider as a mass that sustains all the other rocks known to us. This part of the work before us is particularly curious, and in no other does the Author appear more master of his fubject.

Upon the whole, the principles of M. Sage appear under the pen of our Author to more advantage than they do in his own writings; they are unfolded with more perspicuity and extent, and assume the air of a system : the phosphoric acid acts here a capital part; it forms the basis of metals, precious stones, the

fluor Spars, and is the principle of vitrification, according to Messrs. Sage and Demete. It cannot be denied that certain appearances favour these opinions, such as the zinc's yielding a Aame, the diamond's exhibiting a flame also when exposed to a hot fire, the fusible fpath's yielding a phosphoric Aame, when thrown upon burning coals, and the fixed alkali's producing glass with quartz: nevertheless the doctrine of these ingenious men will require farther proofs and experiments, in order to its complete establishment on the ruins of former opinions.

The second volume of this work, in which nature is to be considered in her different aspects, mineral, vegetable, and ania mal, is in the press, and a speedy publication is announced.

AR T. VIII.
Penfieri intorno a vari Soggetti di Medicina Fisica e Chirurgica, &c.-

Thoughts concerning different Subjects of a Medical Kind, that
have a more immediate Connection with Chirurgery and Natural
Philosophy, in Three Differtations, by DR. FRANCIS BERLING-
HIERI, Professor of Medicine, &c. in the University of Pisa. 8vo.
Lucca. 1778.
T often happens, that after a laborious application to the study

of the theory of medicine, a sagacious and learned physician is at a loss in regard to the use and application of those remedies, whose effects are the most fully ascertained, and which are the

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most frequently employed in the art of healing. This uncer. tainty is partly owing to the still prevailing ignorance of several of the most minute and essential parts of the animal economy, and which has engaged our Auihor to consider (in the first of these dissertations) the obstacles to the improvement and progress of the practice of physic, that arise from the mechanism of the human body, and the erroneous methods of studying it. In treating this delicate and difficult subject, DR. BERLINGHIERI fteers with fagacity and judgment between the credulity of the inedical bigot, and the folly and impertinence of the medical sceptic. He acknowledges his ignorance, and that of his brethren, with respect to many objects, in which the poor patient believes them enlightened, and trusts in them with an implicit faith, and a foolish face of admiration and confidence; and he is not alhamed to advance the following proposition, fo humiliating to the sons of Esculapius, that the numerous and striking discoveries in anatomy, so much celebrated in the last and present centuries, have not, as yet, contributed in the least to the progress and improvement of medical practice. He unveils, in a great many respects, the defects of medical science; and, though he may do real fervice to truth by this modesty and candour, he takes away much illusory comfort (still it is comfort) from the sick, who look up to their medical Popes, as clothed with infallibility, and cooperate successfully with them in the cure, by the effects of this confidence. He observes particularly, that the indications derived from the sensible qualities of the blood and the motions of the pulse, are by no means sure guides, either with respect to the knowledge of the nature or causes of diseases. And after many reflections of this kind, relative to the theory and practice of physic, he proposes fome attempts to correct the noxious qualities of the air in unhealthy places, and more especially in that district of Tuscany which is known under the denomination of Maremmes ; and concludes his dissertation by a judicious plan for directing the studies of the medical youth in the hospitals.

The second Dissertation is thus entitled : Concerning the natural and morbific Fire of the human Body, and certain Diseases which are produced by it. Dr. BERLINGHIERI demonstrates, or, at least, proves, that in the human body, while a ive, there is an inflammation of a peculiar character, which, when it does not exceed a certain degree, nourishes life and health,-that this inflammation, and the heat that results from it, are not produced by the friction which the fluids meet with in passing through their tubes--that this inflammation augments considerably in those parts where the tumour (called inflammatory) is engendered--that this inflammatory tumour can only form itfelf in the nervous parts, and confequently has never its seat in the membrana adipora, or cellular lubstance, which is, on the contrary, very fre

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quently the place where cold tumours are found. Our Author describes with precision and perspicuity the manner in which the inflammatory tumour is formed and increased, proves that the nerves have another property not less essential and distinctive than their fenfibùity, and lays down a theory for the cure of this disorder, which he confirms by experimental proofs of the salutary effects of his medical precepts.—This is followed by a curious discussion concerning suppuration, and pus, in which the Author unfolds points of view, that may be useful in practice, and that are new to us.

He distinguishes pus into two kinds, the one corrosive, and the other he is inclined to call nutritive. This last is produced from the nutritive part of the serum, which divides and precipitates itself like a sediment, when it is in a state of stagnation, and begins to be loaded with a collection of putrid matter.-One of the good consequences of this disquisition is, that it will sometimes prevent our being alarmed, when we see a confiderable quantity of pus or purulent matter issuing from the lungs, the uterus, the vagina, the ureters, since this may happen, says our Author, without any considerable damage, nay sometimes without any damage at all, to these parts. An irritation of the nervés, a weakness in the membranous substance of these parts, is sufficient to occasion a separation of the serous viscous humour that is designed to consolidate their surface, and from thence results the evacuation of pus here mentioned. The method of curing this indisposition furnishes our Author with an occasion of communicating several useful observations.

The third Dissertation (the subject of which is the Dropsy) contains a method of curing that disorder, when lodged in the peritonæum by a chirurgical operation, which is attended with no difficulty and little danger. This operation consists in an incision of three or four fingers breadth made in the membrane which contains the vitiated matter; and this incision must be kept open during the whole time of the cure, both that the entire evacuation of the matter may not be prevented, and that the membrane may be cleansed by proper injections. The falutary effects of this method of cure are abundantly ascertained by unanswerable arguments, that is, by facts. Of twenty-eight persons, says he, who underwent the paracentesis, or tapping, for a dropsy in the peritonæum, not one escaped; whereas of eight, who submitted to the operation already mentioned, only two died, on whom it had not been made with the proper precautions.

The remaining parts of this dissertation exhibit to us reflections on the incisions that may be made in the breast for the cure of pectoral dropfies,-on the paracentesis in the pericardium, when the droptical complaint attacks that party-on the incisions

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