of extracting the acid from the phosphate of mercury, by heat alone. But since the whole of the phosphoric acid is not precipitated by nitrate of mercury, sulphate of magnesia will not be formed on the addition of sulphuric acid, and the magnesia cannot be obtained separate by the same pro

cess.

It may have been in consequence of this oversight, that a mistake on that subject has occurred in the succeeding volume of the Transactions.

A calculus is there described, which had been taken by Mr. Thomas from the bladder of a dog, and a series of experiments are related, from which it was inferred to consist of super-phosphate of lime, and phosphate of ammonia. But from the appearance of this calculus (which was exhibited to the Society at the time when the paper was read) I was much inclined to think that the nature of it was mistaken, and upon full consideration of the experiments, they did not appear to me conclusive.

I therefore obtained a portion of the calculus, and by the following process, the earth contained in it was proved to consist almost wholly of magnesia.

It was dissolved, with the exception of a very small resi duum, by distilled vinegar.

The whole of the phosphoric acid was then precipitated by acetate of lead, added to excess.

The liquor was then poured off, and sulphuric acid was added, which precipitated the excess of lead, and at the same time formed sulphate of magnesia in solution.

By evaporation to dryness, the acetic acid was removed, and by subsequent increase of heat, the sulphate of ammonia and excess of sulphuric acid were expelled,

The residuum being then dissolved in water, and the liquor suffered to crystallize by spontaneous evaporation, there remained a quantity of sulphate of magnesia, that weighed rather more than the quantity of calculus taken for the experiment.

It was evident, therefore, that in this instance, the calculus examined did not consist of super-phosphate of lime, and there is some reason to doubt, whether a compound, that is so very soluble in water, ever forms a part of urinary concretions.

Although the treatment of diseases is not in general a'fit subject to occupy the time of this Society, there is nevertheless one suggestion, with respect to the prevention of calculous complaints, so nearly connected with my present subject, that I think it may deserve to be recorded.

Since the white matter contained in the urine of birds,

which is voided along with their dung, has been remarked by M. Vauquelin to consist principally of uric acid, I have paid some attention to the different proportion in which this matter is voided by different species of birds, to see how far it accorded with the different qualities of their food. And I found that in the dung of the goose, feeding wholly on grass, the proportion did not seem so much as of the whole dung. In that of a pheasant kept in a cage, and fed on barley alone, it was about part. In that of a hen, having the range of a garden and farm-yard, and consequently procuring insects, and possibly other animal food, the proportion was manifestly much greater, and combined with lime. In the dung of a hawk, fed upon flesh alone, the quantity of matter voided in a solid state bears but a small proportion to the residuum of uric acid that is left by the urine when dry. And in the gannet feeding solely on fish, I have observed the evacuations in some instances to be mere urine, for it contained no solid matter, excepting the uric acid.

It seems consequently deserving of inquiry, what changes might be produced in the urine of any one animal, by such alterations of diet, as its constitution would permit; for as far as any inference can be drawn from these varieties, which naturally occur, it would appear, that persons subject to calculi consisting of uric acid, as well as gouty persons, in whom there is always a redundance of the same matter, have much reason to prefer vegetable diet; but that the preference usually given to fish above other kinds of animal food, is probably erroneous.

CRITICAL ANALYSIS

OF

RECENT PUBLICATIONS

IN THE

DIFFERENT BRANCHES OF PHYSIC, SURGERY, AND MEDICAL PHILOSOPHY,

Stock's Life of Beddoes.

(Continued from p. 175.)

IN 1790, Dr. Beddoes published at the Clarendon press, an analytical account of the writings of Mayow; under the title of Chemical Experiments and Opinions extracted from a work published in the last century.

"Till the appearance of this treatise, (observes Dr. Stock) these

L12

brilliant

brilliant discoveries which had outstripped, by upwards of a century, the more tardy advances of other chemical philosophers, had either remained totally unknown, or had received only a scanty or derogatory

notice."

Amidst his other pursuits, Dr. B. cultivated the science of mineralogy with great assiduity and success; and in 1791, read a paper before the Royal Society, entitled, Observations on the Affinity between Basaltes and Granite, in which he aspired to elucidate some of the most intricate questions relative to geology. In the same year he also contributed a valuable paper, containing an account of some appearances attending the conversion of cast into malleable iron. The following year he diversified his studies by writing botanical dialogues.

About this period the memorable revolution which was effecting in France, excited deep interest in every reflecting mind.

"At such a period, it was not an easy task for any person possessed of an independent mind and ardent feelings, to avoid taking a part, and expressing an opinion, upon the important questions which were daily agitating. Dr. Beddoes, at least, was not that man. He hailed the dawn of French freedom with enthusiasm, and cherished, through many a dark and stormy year' hopes of an issue in favour of mankind."

P. 45.

In this year he wrote a treatise upon the subject of carly instruction; and composed a poem, called "Alexander's Expedition to the Indian Ocean."

"This originated," he observes, " in a stratagem, which, if not entirely innocent, can be charged only with the guilt of presumption. In order to impose upon a few of their common acquaintance, the writer, in a few passages at least, attempted to assume the style of the most elegant of modern poets." (Dr. Darwin.)

In this he succeeded, but never ventured to publish the whole of the poem; part of it was inserted in the Annual Anthology in 1796. From the specimens which Dr. Stock has quoted, it seems to possess considerable merit; and many passages bear a striking resemblance to some parts of the "Botanic Garden."

Soon afterwards, he resigned his lectureship at Oxford; and about the same time, published "Observations on the Nature of Demonstrative Evidence, &c. with Reflections on Language." And a medical work, entitled, "Observations on the Nature and Cure of Calculus, Sea-scurvy, Consump tion, Catarrh, and Fever; together with Conjectures upon several other Objects of Physiology and Pathology." In the first division of the work, he speaks of the great efficacy of

alkaline

alkaline remedies in calculus, and especially recommends the carbonate of soda,

"Of which the water of chrystallization has been dissipated by exposure to a warm dry air, or by being spread before a fire. This is combined with rather more than an equal weight of soap, and made into pills. One or two samples of the powder are taken in the course of the day." P. 77.

Immediately upon quitting Oxford, Dr. B. returned to Shiffnal, and having remained there a short time, paid a visit to Ketley. During his residence at this place, he published his celebrated history of Isaac Jenkins; an admirable moral fiction, which gives an account of the Reformation of a drunken Labourer, and his return to Habits of Sobriety and Industry. The success of this little work was extraordinary. Forty thousand copies were disposed of before the end of the year 1796; and the author issued a large impression, a few years since, at the particular request of a society for the promotion of knowledge and virtue by the distribution of books. "It was during this visit also, that he first developed those ideas on the medical use of the permanently elastic fluids, which afterwards attracted such general attention."

A pneumatic establishment was determined upon, and Dr. Beddoes, with three friends, subscribed each 2001. to institute it, Dr. B. engaging to superintend the undertaking; he also voluntarily proposed that the whole of the fe he might receive pending the issue of the experiment, should be devoted to the same purpose.

After encountering many difficulties in the prosecution of his scheme, he succeeded by the friendly agency of Mr. Edgeworth, who happened to be at Clifton at the time, in securing an establishment at the Hot Wells. Our biogra pher informs us,

"The society of this gentleman (Mr. Edgeworth) was a most valuable acquisition to Dr. Beddoes, upon his arrival in a place where he was personally known to so few. There existed between them a similarity of opinion upon a variety of subjects, which rendered their intercourse more pleasant and unrestrained. The science of education, in particular, had already occupied the attention of both, and the practical and enlightened views of the one were still farther extended by the philosophical theories of the other." P. 93.

Dr. Beddoes soon became more intimately connected with this excellent man by marrying one of his daughters. In 1793, he published a letter to Dr. Darwin, containing a farther explanation of his theory of the treatment of consumption, in which he points out two principle varieties of the disease. The one, he terms florid consumption, is denoted by a vivid redness of the checks at the accession of a pa

roxysm,

roxysm, and an extraordinary permanent redness of the lips, tongue, and fauces.

"The eyes too, in such cases, are remarkable for their vivacity. The blood discharged by epistaxis, or hæmoptysis, has a colour evidently more fluid than usual."

From these symptoms of hyperoxygenation, he draws the following inferences.

"It is an evident consequence of my leading opinion, that a phthisical patient would take a longer time than another in being drowned, or in being suffocated in most of those airs that are unfit for respiration. Being already provided, as I suppose them to be, with a larger propor. tion of that principle which respiration introduces into the body, they must be able to continue, for a longer time, without the necessity of a new supply; and as the left cavities of the heart seem to be more irritable in such patients, it is probable they would be more easily recoverable from accidents of this kind, than persons in an ordinary state of health.”

His attention to the effects of different gases in consump. tion procured him the correspondence of many eminent phy sicians, who were gratified with his discoveries, and disposed to assist his inquiries. He was now occupied with considering the means of establishing a hospital for the administra tion of pneumatic remedies; the late accomplished Duchess of Devonshire, who had been much pleased with his appa ratus in Hope-square, entered into the plan with great eager

ness.

"In the mean time, however, he found leisure to publish a little tract, addressed to the more humble classes of society, entitled a Guide for Self Preservation and Parental Affection. In this work, he points out in the most simple language, a variety of errors generally prevalent upon subjects in which health is concerned."

This little tract had a rapid and extensive sale. Dr. Darwin in one of his letters to the author, says of it, "I have read a little work of yours about preserving health with great pleasure. You deserve a Civic crown for saving the lives of your fellow citizens."

Soon after his marriage with Miss Edgeworth, he engaged in the superintendance of a new edition of the works of the celebrated John Brown, for the benefit of his widow and children. His motives for undertaking this task were very honourable to him; we state them in his own words, " to administer this con. solation to men of genius languishing in penury and neglect; that when they are gone from the scene, some notice will be taken, for their sakes, of those nearest and dearest to them."

In this year also, he published, under the title of a " Proposal for the Improvement of Medicine," his plan for determining the power of factitious airs, by the formation of an

institution