ever render its degree of perfection progressive with the advancement of science. In the next place, the classes are in many particulars ill-defined, and indistinctly, if not erroneously, divided. How questionable, for instance, are the boundaries which separate corrosive from acrid poisons? even the respective species of each class are, in many instances, less allied to each other than the great divisions to which they are subordinate. As an exemplification of this fact we have only to compare the physiological actions of arsenic and corrosive sublimate; the former of these substances occasions death by being absorbed, and thus acting as a vital agent, the latter, by its local action as a caustic on the textures with which it comes in contact. In the same manner, if we examine the individual actions of the different species composing the class of "Acrid" poisons, we shall find the same want of uniformity; thus the spurge-flax, and the jatropa curcas, act by occasioning a local inflammation, while the hellebore, being rapidly absorbed, exerts a fatal action on the nervous system, and produces only a very slight inflammation. The class of narcotic poisons is more absolute in its definition, and more uniform in its physiological affinities, and therefore less objectionable, than the divisions to which we have just alluded; but the propriety of the term "Narcotico-Acrid" may be very reasonably questioned; even Orfila expresses his doubts upon the subject, "because the narcotic or sedative effects only follow the previous excitement." Some of the poisons, under this last mentioned class, are rapidly absorbed, and act, through the medium of the circulation, on the nervous system, without producing any local inflammation; whilst others, again, merely act upon the extremities of the nerves, with which they come in contact, and without being absorbed, occasion death by a species of sympathetic action.

These few objections, and many more might be adduced, are sufficient to demonstrate the imperfection of the classification under consideration, and which would render it wholly unavailable to the pathologist who must adopt his treatment according to the physiological action of each poison. The author has accordingly, in his "Pharmacologia," ventured to propose an arrangement, in conformity with such views; and the following sketch of it may perhaps form a useful introduction to the general observations which it will be hereafter necessary to offer upon the "modus operandi" of poisons.

A CLASSIFICATION OF THE DIFFERENT MODES BY WHICH POISONS PRODUCE THEIR EFFECTS.

1. By acting through the Medium of the Nerves, without being absorbed, and without exciting any local Inflammation.

a. By which the functions of the nervous system are

Acrid. Aconite. Jatropa Curcas.

destroyed,

Narcotico-Acrid.

Alcohol.

Oil of Tobacco.

Narcotic.

Essential Oil of Almonds.†
Camphor.t

Opium †?

b. By rendering the heart insensible to the stimulus of the blood.

Infusion of Tobacco.

Upas Antiar,

II. By entering the Circulation, and acting through that Medium with different Degrees of Force, on the Heart, Brain, and Alimentary Canal.

III. By a local Action on the Mucous Membrane of the Stomach,

exciting a high Degree of Inflammation.

+ This mark denotes that the substance against which it is placed, may also act by being absorbed.

Signifies that the article has also a local action.

The preceding classification of poisons will not only furnish the practitioner with a general theorem for the administration of antidotes, but it will suggest the different modes and forms of administration of which each particular substance is susceptible; it will show that certain poisons may occasion death without coming into contact with any part of the alimentary canal, and that others will produce little or no effect, however extensively they may be applied to an external surface. The first class comprehends such poisons as operate, through the medium of the nerves, upon the organs immediately subservient to life; in the application of such agents it is obvious that they cannot require to be introduced into the stomach, they may convey their destructive influence by an application to any part duly supplied with nerves, and whose extremities are exposed to their action; although at the same time, it may be observed that, in general, poisons of this kind act most powerfully when internally administered, owing to the extensive sympathetic relations of this central organ over every function of the living body. The second class consists of poisons that are incapable of producing any effect, except through the medium of the circulation; whence we shall be enabled to explain and appreciate the various circumstances which may accelerate or retard their operation. Poisons of this class may be applied externally to abraded parts, or even to surfaces covered with cuticle, provided their absorption be promoted by friction; and it may be here observed, that the function of absorption is not performed with the same force in every tissue; as a general proposition, it may be said to be energetic in proportion to the number of lymphatics and veins, although the late experiments of M. Majendie have shown how greatly it is influenced by the state of the circulation. If these poisons be administered internally, they find their way into the circulating current either through the branches of the thoracic duct, or those of the vena portarum; when, as if by a species of election, each substance very frequently expends its venom upon some one particular system of organs. Many of the substances arranged under this second division have moreover a local effect upon the structure with which they first come in contact; it is thus with colocynth, and some other bodies; while, on the contrary, several of those poisons which are distinguished for their local action, are subsequently absorbed, and are thus, as it were, enabled to ensure their work of destruction by a double mode of operation. We shall receive ample evidence of this truth, as we proceed in the history of particular poisons. The third class comprises such agents as inflict their vengeance upon the mucous membrane of the stomach, by actual contact, and destroy, by exciting local inflammation.

ARTICLE IV.

Analysis of James's Powder. By Richard Phillips, FRS. L. & E.

IN the Annals for October, 1822 (New Series), I gave án analysis of the pulvis antimonialis of the London Pharmacopoeia, by which it appeared that this medicine, procured from two respectable sources, differed very little in composition. The mean of the two results showed this preparation to be composed of

Peroxide of antimony.
Phosphate of lime..

36.5

63.5

100.0

Several medical friends have since inquired of me, whether I had made any experiments upon James's powder, which has been shown by Dr. Pearson to consist of oxide of antimony and phosphate of lime. In answer to these inquiries, it might have appeared sufficient to refer to Dr. Pearson's analysis, published in the Philosophical Transactions for 1791. In the course of 30 years, however, chemical research has been so actively pursued, that it would be very remarkable if the nature of the oxides of antimony was not better understood than when Dr. Pearson performed his analysis. Without, however, entertaining any suspicions that the results of his investigation were incorrect, it appeared to me to be a subject worthy of further inquiry, whether the antimony in this powder is in the same state as I found it to be in the antimonial powder. The nature of the oxide formed no part of Dr. Pearson's inquiry, nor was the difference of power between the protoxide and peroxide of antimony so well understood as at present.

Having procured some James's powder,* I first directed my attention to the effect produced by boiling it in distilled water; my reason for this was to ascertain whether it contained any tartarized antimony, a suspicion of which was entertained by the late Dr. George Fordyce.

The water in which the powder had been long boiled was extremely turbid, and remained so for a long time; nor could I render it perfectly clear even by filtering it through several folds of paper.

On adding some solution of sulphuretted hydrogen to the filtered but slightly turbid water, perceptible traces of the presence of oxide of antimony were indicated by the appearance of the well-known orange-coloured precipitate; the effect was, how

From Messrs. Newberry's, St. Paul's Church-yard.

ever, so very trifling, that I am induced to attribute it entirely to the oxide of antimony suspended in the water, and not to any which it held in solution. To another portion of the solution, I added nitrate of lead; it was rendered rather more turbid by this addition, but not in a greater degree, than might be expected to arise from the presence of phosphate of lime, which is sufficiently soluble in water to be detected by reagents. Had tartarized antimony been present in such quantity as to influence the nature of the preparation, a copious precipitation of tartrate of lead must have occurred, instead of the slight turbidness described. Judging from the effects which I have now detailed, I am certainly of opinion that James's powder does not contain any tartarized antimony, or any combination of it which is soluble in water.

Fifty grains of James's powder were now boiled in an ounce of muriatic acid diluted with an equal bulk of water, and the ebullition was continued long after any of the powder appeared to be dissolved by the acid. It was evident that a very large proportion of the powder subjected to experiment remained undissolved. This circumstance perfectly satisfied me, that although James's powder might possibly contain some protoxide of antimony, a very large portion was evidently peroxide. I may here remark, that the degree of insolubility of this or any powder containing oxide of antimony, furnishes a ready mode of estimating its power; the less which is left undissolved, the more active the remedy; for, excepting under peculiar circumstances, peroxide of antimony is nearly insoluble in muriatic acid; and when it has been once subjected to a red heat, a very small quantity escapes such a degree of cohesion as to remain soluble in an acid.

Having suffered the muriatic solution to become clear by subsidence, I poured some of it into a large quantity of water; not the slightest precipitation occurred: it was, therefore, evident that but little, if any, oxide of antimony had been taken up by the muriatic acid.

I

As the excess of muriatic acid employed was considerable, I thought it might possibly retain the oxide in solution even after dilution with water. To discover whether this was the case, added carbonate of soda to the muriatic solution until precipitation commenced. I then poured it into a solution of potash, taking care to have such an excess of the alkali as would immediately redissolve any oxide of antimony which might be at first precipitated.

In order to be certain that any oxide of antimony which the muriatic acid had dissolved should be taken up by the potash, the alkaline solution, containing the precipitated phosphate of lime, was boiled for a considerable time; the clear solution was poured off, and saturated with acetic acid, by which a very small quantity of precipitate was obtained. When this had been