Oldalképek
PDF
ePub

different properties in other respects : I found that the decoction of Gruyere cheese formed an abundant precipitate with tannin.

20. That azote enters into the composition of the putrid gas, forming without doubt with hydrogen a combination of an equilibrium less stable than ammonia, or rather an intermediary combination ; but when its proportion is dimi. nished to a certain point, it is more strongly retained by the substance, and it ceases to produce putrid gas. This substance, which the putrid odour characterizes, seems rather to be a very evaporable combinațion, allied to all the gases like the other elastic vapours, than a permanent gas.. .

3d. Since the caseous part has less azote than most othér animal substances, we may conjecture that during life this part is animalized more and more by acquiring a greater proportion of azote and hydrogen : this may be explained by the more intimate combination of oxygen and hydrogen which enter into its composition, and by a separation of the carbon by the act of respiration; so that the last term of che mical action during life has urea for its product, according to the opinion of M. Fourcroy. .

A new and expeditious Mode of Budding. By THOMAS

: ANDREW Knight, Esq. F.R. S.

[ocr errors]

[Transactions of the Horticuitural Society of London.}. i sig PARKINSON, in his Paradisus Londoniensis, which was published in 1629, has observed, that the nurserymen of his days had been so long in the practice, of substituting one va. riety of fruit for another, that the habit of doing so was almost become hereditary amongst them : were we to judge from the modern practice, in some public nurseries, we might suspect the possessors of them to be the offspring of intermarriages between the descendants of those alluded to by Parkinson. He bas, however, mentioned his 66 very good friend, Master John Tradescant” and “ Master John Miller,” as exceptions; and similar exceptions are, I believe, to be found in modern days. It must, however, be admitted, that wherever the character of the leaf does not expose the error of the grafter, as in the different varieties of the peach and nectarine, mistakes will sometimes occur; and Therefore a mode of changing the variety, or of introducing a branch of another variety, with great expedition, may possibly be acceptable to many readers of the Horticultural Transactions.

The The luxuriant shoots of peach and nectarine trees are generally barren ; but the lateral shoots emitted in the same season by them are often productive of fruit, particularly if treated in the manner recommended by mc in the Horticultural Transactions of 1808, p. 88. In the experiments I have there described, the bearing wood was afforded by the natural buds of the luxuriant shoots; but I thought it probable that such might as readily be afforded by the inserted buds of another variety, under appropriate management. I therefore, as early in the month of June, of the year 1808, as the luxuriant shoots of my peach trees were grown suflici. ently firm to permit the operation, inserted buds of other varieties into them, employing two distinct ligatures to hold the buds in their places. One ligature was first placed above the bud inserted ; and upon the transverse section through the bark : the other which had no farther office than that of securing the bud, was applied in the usual way. As soon as the buds (which never fail under the preceding circumstances) bad attached themselves, the ligatures last applied were taken off, but the others were suffered to remain. The passage of the sap upwards was in consequence much obstructed, and the inserted buds began to vegetate strongly in July: and when these bad afforded shoots about four inches long, the remaining ligatures were taken off, to permit the excess of sap to pass on; and the young shoots were nailed to the wall. Being there properly exposed to light, their wood ripened well, and afforded blossoms in the succeeding spring : this would, I do not doubt, have afforded fruit; but that, leaving my residence at Elton for this place, I removed my trees, and the whole of their blossoms in the last spring proved, in consequence, equally abortive.

NON

On Cystic Oxide, a new Species of Urinary Calculus. By WILLIAM HYDE WOLLASTON, M. D. Sec. R. S.

[Phil. Trans. Part 2. 1810.] THE principal design of the present essay is to make known the existence, and to describe the leading properties, of a new species of urinary calculus from the human bladder ; but I shall at the same time take the opportunity of correcting an inaccuracy or two that I have observed in my former communication on this subject. (Phil. Trans. 1797.)

I on that occasion took notice of five kinds of urinary calculi. 1. The lithic acid, since called uric acid, originally analysed by Scheele.

1. 2. The

hate of lime, hate of magnesia: the two l

2. The oxalate of lime, or mulberry calculus. . 3. The phosphate of lime, or bone-earth calculus. 4. The ammoniacal phosphate of magnesia. 5. The fusible calculus, which consists of the two last

species combined. It is now about five years since I first met with another species, evidently differing from each of those before described. It was in the possession of Dr. Reeve, of Norwich, who obligingly gave me a portion of it for the purpose of examining its chemical qualities. It had been taken from his brother when he was five years old, and at that time was covered with a coating of phosphate of lime very loose in its texture, and consequently very soon separated.* This species is probably very rare ; for, although I have omitted no opportunity of paying attention to any urinary concretions to which I could have access, I have, to this time, seen only one other specimen of the same substance. This last is in a collection of calculi belonging to Guy's Hospital, given by Mr. Lucas, surgeon to that institution, having been formed partly by his father, and partly by himself, in the course of their practice ; and according to the present arrangement, (which, it is hoped, will not be altered) the calculus to which I allude may be found by reference to No. 46 of that collection. It was extracted by the usual operation, from a man of 36 years of age, of whom no record is preserved, except that his name was William Small. It weighed, when entire, 270 grains.

In appearance, these calculi resemble more nearly the triple phosphate of magnesia, than any other calculas ; but they are more compact than that compound is usually found to be: not consisting of distinct laminæ, but appearing as one mass confitsedly crystallized throughout its substance. Hence, instead of having the opacity and whiteness observable in fusible calculi, which consist of a number of small crystals cemented together, these calculi have a yellowish semi-transparency; and they have also a peculiar glistening lustre, like that of a body having a high refractive density.

When this substance is submitted to destructive distilla

•* I am informed that another stone formed afterwards in the bladder of this boy, and that he died in consequence, without submitting to the operation a second time. The stone found in his bladder after death, consisted principally of uric acid, but was peculiar in one respect, as its centre was hollow by the removal of some more soluble substance, of which the nucleus had consisted.

tion, it yields fætid carbonate of ammonia, partly fluid, and partly in a solid state, and a heavy foetid oil, such as usually proceeds from animal substances; and there remains a black spongy coal, much smaller in proportion than is found after the distillation of uric calculi.

Under the blow-pipe it may be distinguished from uric acid by the smell, which at no period resembles that of prussic acid ; but in addition to the usual smell of burnt animal substances, there is a peculiar fætor, of which I can. not give a correct idea, as I know no smell which it can be said to resemble.

This species of calculus is so readily acted upon by the generality of common chemical agents, that its character I may perhaps be most distinctly marked, by an enumeration of those feeble powers that it can resist.

It is not dissolved (excepting in very small proportion) by water, by alcohol, by acetic acid, by tartaric acid, by citric acid, or by saturated carbonate of ammonia.

The solvents, on the contrary, are far more numerous. It is dissolved, in considerable quantity, by muriatic acid, by nitric acid, by sulphuric acid, by phosphoric acid, and by oxalic acid.

It is also dissolved readily by pure alkaline menstrua : by potash, by soda, by ammonia, and by lime-water. It is even dissolved by fully saturated carbonates of potaslı or of soda. Accordingly, thesc alkalies are not so convenient for the precipitation of this matter from acid solutions, as the carbonate of ammonia, which is not capable of redissolving the precipitate, though added in excess.

For a similar reason, the acid best snited for its precipitation from alkaline solutions, are the acetic and citric acids. But the tartaric acid may occasion an appearance of precipitation, by forming a supertartrate with the alkali employed.

T'he combination of this substance with acids may be made to crystallize without difficulty, and they form slender spicula radiating from a centre, which readily dissolve again in water, unless they have been injured by being in any degree 'over-heated.

The muriatic salt is decomposed by the heat of boiling water, on account of the volatility of the acid, and the rest are easily destroyed by a greater excess of heat.

The salt formed by combination with nitric acid, does not yield oxalic acid, and does not become red, as the uric acid does, when similarly treated; but it turns brown, becoming gradually darker, till it is ultimately black. When the combinations with alkalies are evaporated, they leave small granular crystals; but as I was desirous of rendering my experiments as numerous as a limited quantity would permit, the portion which I could employ in any one expe. riment was too small for me to attempt to determine the form of such crystals.

When a hot solution in potash was neutralized by distil. led vinegar, the precipitate did not immediately take place, but formed gradually during the cooling of the liquor in mi. nute crystals, some at the surface of the fluid, and others attached to the sides of the vessel. The only definite form which I could observe, was that of flat hexagonal plates, but I could discern nothing which enabled me to judge of the primitive form of the crystal. On the surface of the calculus' belonging to Guy's hospital, some minute crystals may be discerned, of a different shape, being nearly cubic. And it is possible, that the bexagonal crystals may owe their figure to a small portion of alkali remaining in combination.

From the ready disposition of this substance to unite with both acids and alkalies, it would appear to be an oxide; and that it does, in fact, contain oxygen, is proved by the fore mation of carbonic acid in distillation. The quantity of oxygen present in the calculus is not, however, sufficient to give it acid properties, for it has no effect on paper coloured with litmus.

I am therefore inclined to consider it as an oxide : and since both the calculi that have yet been observed have been taken from the bladder, it may be convenient to give it the name of cystic oxide, which will serve to distinguish it from other calculi; and as this is unlike any other term at present employed in chemistry, it is to be hoped that it will not be thought to require any alteration.

Since the period of my first essay on gouty and urinary concretions, the general results contained in it have been confirmed by others, and I believe are incontrovertible. But I am under the necessity of acknowledging a mistake in the analysis of the mulberry calculus, though not of much im portance. An acid is mentioned to have arisen by sublimation, and it was supposed to originate from a partial decomposition of the oxalic acid. But since pure oxalate of lime yields no such sublinate, it most probably arose from the mixture of a small quantity of uric acid in the calculus then under examination.

In the analysis of the triple phosphate of magnesia, there is another mistake of more consequence. In my selection from numerous experiments for ascertaining the presence of phosphoric acid, I gave the preference to one in which nitrate of mercury was employed, on account of the facility

(No. 145.)

LI

L'of

« ElőzőTovább »