• Animal Albumen is generally found in the form of a transparent uid more or less viscous, and of an aqueous colour, tending to a yellow.

Its savour is slightly saline, and if tasted with attention, somewhat sharp.

It changes the syrup of violets green.

It is soluble in cold water.

< Alkalis dissolve it.

• Acids coagulate it.

Lime water produces a precipitation in the albumen, which is the phosphate of lime. It is coagulated by the metallic oxydes, and by alcohol.

It decomposes, and causes a precipitation in solutions of neutral, calcareous, and metallic salts.

It undergoes the putrid, but not the acetous fermentation.

The most distinguishing character of this fluid is, that when exposed to a degree of heat from 45° to 48°, (80° being the boiling point,) its liquidity and transparency disappear, it becomes opake, concrete, and solid.'

We suspect, from these propositions, that the author has confounded the pure albumen with this substance as it exists in the serum of the blood, or the white of the egg. Its saline taste, and its effect on syrup of violets and lime water, as here described, must certainly depend on the presence of alkaline and phosphoric salts.-We are at a loss to know what can be meant by an aqueous colour.-In enumerating the changes which it undergoes by coagulation, it is said that it (coagulated albumen) is insoluble in caustic alkalis: but this assertion is completely erroneous.-No mention is made of the effects of tan on the albumen.-In speaking of the cause of its coagulation, too much importance is attached to the opinion of Fourcroy, that it depends on the absorption of oxygene; for not only were his own experiments inadequate to prove this point, but the hypothesis has been directly controverted by the subsequent experiments of Carradori, who found that the operation was in no degree retarded, when performed in such a manner as absolutely to exclude all access of oxygene. No reference is made in this place to the experiments of Carradori, though, in a former part of the work, his objections to Fourcroy's hypothesis are fairly stated.

The contents of Vol. III. are divided into two parts, under the titles of Life and Death. The first section contains remarks on the vital principle, irritability, respiration, and animalization.' Respiration being the most important of these subjects, and the one to which the author seems to have devoted the greatest share of attention, we shall examine, at some length, the manner in which it is treated.

REV. OCT. 1805.

After some observations on the organs of respiration in dif. ferent classes of animals, we are presented with a brief sketch of the opinions that were successively entertained by the older writers, respecting the nature and use of this function. Nothing worthy of attention occurs in the history of this science, until the publication of Mayow's tracts; and Mr. Johnson gives a good account of his leading discoveries and hypotheses. Though we think that he represents them in rather too fa vourable a light, we are disposed to acquiesce in his conclusion:

No philosopher, at the end of the last century, had given any theory of combustion and respiration, or any account of the analogy between these two natural phænomena; of the reciprocal influence between them and the air; and of the effects produced by this fluid compared with those of nitre in combustible bodies, with so much detail and sagacious ingenuity as this physician. His works form an epoch in the annals of respiration. In giving Mayow all the merit due to him, it appears, however, that although he had determined with great precision the use of the nitro-aerial spirit of the atmosphere to be to warm the blood and give it its brilliant red colour, he was ignorant whence these phænomena arose, and how the air contributed to it and although these nitro-aërial and igneo-aërial particles may be looked upon as the vital air or oxygen gas of the moderns, he knew nothing of its properties, nor of the change it underwent by the action of flame and respiration. These explanations were reserved for Priestley and Lavoisier.'

Referring to the writings of Hales, Haller, and Cigna, Mr. J. details the experiments and discoveries of Dr. Priestley on respiration, and then proceeds to those of M. Lavoisier.

We have next, rather aukwardly introduced, an account of the experiments performed by Jurin, Goodwyn, Menzies, and others, to ascertain the capacity of the lungs, and the change of bulk which they experience in the process of respiration. Their operations are reported at considerable length, and will be found to differ very materially from each other; yet the author makes no attempts to reconcile them, and offers no remarks on their respective merits, nor on the sources of inaccuracy into which some of these physiologists must necessarily have fallen. We were much surprized not to meet, in this place, with an account of Mr. Davy's experiments on the subject; which are highly deserving of attention, not merely on account of the celebrity of the author, but because, notwithstanding the ingenious manner in which they were contrived, and the apparent accuracy with which they were performed, their results differ very materially from those that were obtained by preceding physiologists. Though these are perhaps the only experiments that are intitled to any great degree of consideration,

sideration, yet there are others, as those of Jurine of Geneva, De la Metherie, Kite, and Abernethy,-which ought at least to have been mentioned in so extensive a work as the present.

The change of colour, which the blood experiences in respiration, next comes under notice. The real cause of this change, though ohscurely intimated by several of the older writers, was first clearly developed by Dr. Priestley; and allowing for the peculiarity of his phlogistic theory, his explanation of the phænomena was nearly that which was afterward adopted by M. Lavoisier; they supposed that, when the blood had its colour heightened by passing through the lungs, the effect was produced by the oxygenous part of the atmosphere removing from it a portion of its inflammable matter. A subsequent theory, and one which is on the whole more consonant to fact, attributes the change of colour to an absortion of oxygen by the blood; an hypothesis which owes its chief support to the experiments of La Grange and Hassenfratz. Neither the objections that have been urged against the former theory, nor the arguments that have been brought in support of the latter, are here so clearly stated as we could have wished; and the reader is left, as usual, without any guide to direct his judgment in the choice of the one or the other of them.

The curious and important question respecting the origin of animal heat now comes to be considered. After a brief sketch of the crude notions that were formed on this subject by the older physiologists, Mr. Johnson elucidates at some length the ingenious opinions of Dr. Crawford. The account of this celebrated hypothesis is detailed with a considerable degree of perspicuity, but still with too much of that prolixity which we have already been obliged to condemn.

Mr. Johnson's method of stating at full length, and almost in their own words, the experiments and deductions of the different writers whom he consults, not unfrequently leads him into erroneous statements. For instance, he introduces a string of propositions translated, though without acknowlegement, from Lavoisier, in which it is asserted that the atmosphere consists of 27 parts of oxygen, and 73 of azote. This was formerly thought to be the correct analysis: but subsequent experiments, made with more accurate instruments, have established the proportion of oxygen to be about 21 parts only. An analogous remark may be applied to the carbonic acid gas. Lavoi sier had calculated that carbonic acid was composed of 72 parts of oxygen and 28 of carbon, and this estimate is implicitly assumed by Mr. Johnson. It has, however, been decisively proved that charcoal is not, as Lavoisier conceived, a simple substance, but is itself in the state of an oxyd, containing .36 of oxygen; so that 18 parts only of pure carbon can

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enter into the composition of carbonic acid.-Another, but perhaps still more reprehensible instance of the same kind of negligence, occurs in this and other parts of the volumes before us; where the author, in his extracts from the French writers, has not even taken the trouble of converting the thermometrical degrees of their scale to the corresponding degrees of the scale generally adopted in this country. Speaking of the experiments made by Lavoisier, to determine the quantity of heat generated in a given time by the respiration of a guineapig, he informs us that they were performed at the temperature of 14 or 15 degrees.

An ample abstract is inserted, or rather a translation, of the memoir of Lavoisier on transpiration; the last which this philosopher lived to complete. Though we cannot but admire the ingenuity manifested in the contrivance, and the perseverance displayed in the execution, of the experiments detailed in this paper, we confess that there have always appeared to us several strong objections against the conclusions deduced from them by their celebrated author. We do not perceive how his apparatus could keep the effects, of what he calls pulmonary transpiration, distinct from those which properly belong to respiration; yet, if these be confounded, the grand object of the experiments is destroyed. Indeed, it may be inferred from some expressions in the paper itself, that Lavoisier was aware of this deficiency; and that he proposed to remedy it in a future set of experiments, which his untimely fate prevented him from executing. Before his conclusions can be fairly established, it would be also necessary that the quantity of water actually emitted by the lungs should be collected and measured but it does not appear how this was effected. It may be farther remarked that Lavoisier always proceeds on an estimate of the composition of carbonic acid, which has been since proved to be erroneous. We deem it, however, unnecessary to enter more at large into the consideration of this paper. Mr. Johnson appears to have wholly acquiesced in the reasoning employed in it; and he copies both the experiments and the inferences drawn from them, without any remarks on their merits, or on the confidence which ought to be placed in them.

Mr. J. next furnishes an account of experiments on the respiration of fish and insects; and the subject concludes with a copious abstract of Mr. Davy's experiments on the respiration of nitrous oxyd, occupying between 40 and 50 pages, and given very nearly in the words of the original, without any observations on it. At the end of the section, as in other cases, we find a long and certainly valuable list of the sources whence the author has derived his materials. Again, how

ever,

ever, we have to remark that it is very defective. The older writers are entirely omitted; and though, with respect to most of them, we might pardon the oversight, certainly such names as those of Lower, Keill, and Boerhaave, should have been noticed in a complete history of animal chemistry. Among the more recent philosophers, the experiments of Jurine, Higgins, and Abernethy, are not noticed; nor do we find any reference to Seguin's valuable essays in the Annales de Chimie, to Mr. Coleman's Dissertation on Respiration, to Dr. Beddoes's work on Factitious Airs, to Dr. Thomson's account of respiration in the supplement to the Encyclopædia Britannica, and in his System of Chemistry; and, to pass by all minor errors, we look in vain for four of Lavoisier's most valuable dissertations on this subject, viz. two in the Memoirs of the Academy of Sciences for 1777; one in the Memoirs of the Medical Society for 1732; and one in the Memoirs of the Academy for 1789. We would strongly recommend it to Mr. Johnson to peruse these papers, previously to any future attempts to write on respiration.-Before we close these criticisms on the list of references, we must observe that, besides the deficiencies which occur, the works that are enumerated are not always correctly designated. Hassenfratz's paper, on the combination of oxygen with the blood, is stated as if it were to be found in the Memoirs of the Academy for 1791: but the fact is that no such volume exists; the paper was indeed read to the Academy in the year 1791, but was printed in the 9th volume of the Annales de Chimie.

In addition to these remarks, it will scarcely be necessary to state our opinion more fully on the merits of Mr. Johnson's work. It is a laborious collection of facts, which, though not without some errors and deficiencies, are for the most part accurately stated: but they are thrown together without either arrangement or selection, and we find not the least portion of the philosophy of chemistry. With respect to the style, it may be intitled to the praise of being generally intelligible, and free from affectation: but it is crude and inelegant, and not unfrequently defaced by inaccuracies which betray either great ignorance, or culpable negligence.

ART. III. A Northern Summer; or Travels round the Baltic through Denmark, Sweden, Russia, Prussia, and Rart of Ger many, in the Year 1804. By John Carr, Esq., Author of the Stranger in France*, &c. &c. 4to. pp. 480. and 11 Plates. 21. 2s. Boards. R. Phillips. 1805.

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T is of the nature of man to assimilate his ideas in some degree with those of every writer whom he peruses. Hencewe See Rev. Vol. xli. N. S. p. 393.

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