The CHAIRMAN said that if he were bitten by a mad dog, he would not like to trust to the remedy here proposed.

Great Britain, it seemed to me that further attention Tuscany, its chief source being the Val di Chiana, where should be paid by qualified men to a medicine which has the peasants collect it by spreading cloths under the a certain repute in several parts of Europe for curing trees morning and evening, and shaking the insect out the bites of mad animals. Dr. Grisanowski, of this city, of the branches. The months of May and June are kindly informed me of its use in Russia and France, and those in which the gathering takes place, and the fly has supplied me with information on the subject. It prefers the Olive-tree to the Poplar and Ash, which they appears that about thirteen or fourteen years ago a also frequent. They are killed by being plunged into certain Nikititsch Levachoff, of Peklitz (Government of weak vinegar, or by being held over the steam of the Riazan, Russia), created a sensation by his cure of hy- same. Afterwards they are dried as rapidly as possible drophobia. His arcanum was supposed to be the Cetonia in the sun, and are frequently turned over by a thickly aurata, or rose beetle. The monks of Phaneromenos, gloved hand, or by other means. near Eleusis, Greece, use the insect Mylabris bimaculata, with equal parts of the leaves of Cynanchum excelsum, in doses of 15 grains of the mixed powder; at the same time they cauterize the wound with boiling oil. The physician of the late King Otho, of Greece, often gave half-grain doses of cantharides, until symptoms of incipient gastro-enteritis declared themselves. Here in Tuscany there are one or two persons who are reputed to be able to treat successfully the bites of mad animals by means of a nostrum whose basis is supposed to be cantharides, or other insects with blistering properties; and it appears that their efforts are not unavailing, inasmuch as a medical man, to my knowledge, was convinced the Pharmaceutical Conference at Liverpool, of Mr. of the efficacy of the remedy, and caused a number of bottles to be prepared by one possessing the secret, and forwarded them, with a memoir, to the Academy of Medicine at Paris. As the box containing the remedy must

Dr. ATTFIELD read a paper en

SOLUTIONS.

BY T. B. GROVES, F.C.S.

A short discussion that ensued on the reading, before

in water.

Rimmington's paper on "The Specific Gravity and the Actual Weight of Certain Volume Measures of Various Liquid Preparations," set me inquiring on the subject of the volume occupied by salts when dissolved have arrived at its destination but a short time before The statement credited to the President by the reporter the breaking out of the recent war, it is probable that' the whole matter has been set aside and forgotten. of the PHARMACEUTICAL JOURNAL is to this effect, "That Speaking of the remedy to the physician, I suggested to the contents per oz. were coincident with the specific him that it contained cantharides, to which he assented, gravity; for instance, lemon-juice having a sp. gr. 1·040or supposed that at least some blistering fly entered into would contain 40 grs. of citric acid per oz., and so on, the composition; and it then occurred to me that I had except in such cases as alum and sulphate of soda, where once copied an ancient recipe for hydrophobia, and that there is much water of crystallization. In those cases it out of curiosity I had retained a copy for myself. Proba- would be half, or 20 grs. per oz." bly the two compounds are identical. The formula in my possession was represented as a secret left by S. Donnino to the family of Boccaccio, and is represented by the following translation:

It may be taken from the day of the bite up to twentyfive days after. The remedy must not be administered to pregnant women. It is to be taken in one dose according to age, as marked above, in wine, broth or water, according to the taste of the sick person. It must be administered fasting, and the patient should not eat any thing for at least four hours, and during this time should take a great deal of exercise, in order that the remedy should act the more. The patient will suffer strong pains in the head and kidneys, besides other inconveniences; even to the passing of bloody urine, should the dog have been really mad, and the blood have commenced to be contaminated. If at the height of the pain the patient would like to drink a glass of Nocera or Lettuccio water, it will serve him as a relief.

Remarks.-Tuscan grains have the value of 5 centigrams; consequently are less than the grain employed in Great Britain, Germany, etc. Nocera water is derived from a source in the Central Apennines, and Lettuccio water is the produce of one of the springs at Montecaline in Tuscany. It has laxative properties, and is less nauseous than many other purgative waters.

The Cantharis vesicatoria is found in several parts of

Mr. Reynolds followed with the remark, that the same rule applied to sugar in diabetic urine, but properly qualified the assertion by the phrase "roughly speaking.

In the cases of both lemon-juice and urine, the estimation by that method must necessarily be exceedingly rough, as the variations in the proportions of other constituents affecting the specific gravity of the fluids are left out of the question entirely.

Although I have no new experiments to offer, I shall,. I think, be doing some service, if I recapitulate shortly the facts I have ascertained in the course of my recent reading on this subject. It will, at least, serve to caution some who otherwise would be inclined to place too implicit reliance on the "rough methods," already referred

to.

Dalton, during the latter part of his life, occupied himself with the question of solution, and derived from his experiments this supposed law, "that when a body dissolves, it will only increase the volume of the solvent in proportion to the water of crystallization it contains." His method of research involved the use of two measuring vessels, and pouring backwards and forwards, in fact, was quite incapable of giving accurate results.

This, as well as the want of general applicability of his laws, was pointed out by Hilton, whose volumenometer, consisting of a glass flask with a long, narrow, graduated neck, enabled the experimenter to approach more nearly to accuracy of determination. He found that whilst the theory approached correctness in the cases of desiccated sulphate of magnesia and carbonateof soda, it completely broke down in the cases of the naturally anhydrous salts, nitrate of potash, sulphate of potash, etc.

Walker found, to his astonishment, sometimes an expansion, sometimes a contraction of the whole volume of salt and water, according to the nature of the salt employed, and the strength and temperature of the solution. However, he does not appear to have commenced with very clear notions, for after repeatedly employing the terms "bulk" and "volume," he goes on to say, “I

Ratio of

1:20
1:10

next proceeded to determine if the increase of volume
had any relation to the specific gravity of the different Sugar and Water.
substances, or if, when a known weight of salt was dis-
solved in water, the increase of volume was in proportion
to the volume, as indicated by the specific gravity, and
if so, the salt would dissolve without either expansion or
contraction." Did he really expect an ounce of sulphate
of magnesia, for instance, to occupy the same space as an
ounce of water!

This method involved the use of a volumenometer. The one employed was not so well adapted for the attainment of accurate results as that of some other experimenters, but was, on the whole, far superior to that of Dalton.

Nitrate of potash was the first salt employed in testing the value of his new idea. The specific gravity of nitrate of potash being, according to his determinations, 2-074, one hundred grains of the salt would occupy the space of 48-21 grains of pure water. The calculated specific gravity would therefore be found thus,-100 grs. of salt being dissolved in 500 grs. distilled water—

But the specific gravity ascertained by experiment was 1-1100, showing, according to him, a condensation amounting to 6-22 grain measures.

1:1
3:1

The temperatures here even are not uniform. I may observe that when the ratio is 1:1, the sugar occupies a volume very nearly co-incident with that due to its specific gravity 1.606.

The investigation included the determination of a vast number of specific gravities and solution volumes of salts of every description. In compiling the following, table I have selected a few only of special interest, considered pharmaceutically. The specific gravities are, in general, not those of Playfair and Joule, but those obtained by H. Buignet through the use of the Air Volumenometer invented by Regnault; and therefore, I consider, more worthy of acceptance. The term "specific gravity in solution," I employ simply to designate the weight of the solvend in air divided by the space it occupies in the solvent :

Name of Salt.

Soda

I certainly cannot deduce this amount from the data given, but make it 77 gr. m. However, the principle Sulphate of Copper being established, it becomes possible when the ratio of condensation of a salt is known, to calculate the specific gravity of a solution within certain limits of accuracythose limits being defined by temperature and degree of dilution.

The effect of dilution as exemplified in the case of a saturated solution of nitrate of soda is shown to be the following:

If to 430 gr. m. of a saturated solution 60 gr. m. of water be added, the mass will suffer a decrease of volume of 1 gr. m. Sulphate of magnesia behaves in the same manner, and to the same degree. Nitrate of potash suffers a diminution of 5 gr. m., muriate of ammonia 25 gr. m. under the same circumstances.

From a long and laborious paper by Messrs. Playfair and Joule, describing a series of experiments undertaken in order to ascertain whether there really existed any similarity between solid and gaseous combinations, in respect of the law of equal or multiple proportions observed first by Gay-Lussac in the case of gases,-I propose to select those facts only that seem to have some pharmaceutical interest, and are possibly capable of practical application, omitting reference to the theoretical deductions therefrom further than to say that they have since been roughly handled by Professor Marignac, of Geneva, whose criticisms appear to me to well deserve consideration.

accuracy.

Biborate

Chloride of Calcium
Potash Alum.
Ammonia
Carbonate of Soda
Sulphate of Magnesia
Iron.
Nitrate of Potash
Soda

Ammonium

Chloride of Potassium
Bromide of Potassium

Iodide

Soda
Oxalate of Ammonia
Sugar

all bodies, and mixtures of bodies, on the verge of change Bearing in mind the irregularity that seems to attend of state, and, therefore, confining oneself to solutions of mean condition, neither extremely strong nor excessively weak, it is possible by means of this table to ascertain beforehand, with tolerable accuracy, the effect of mixing definite quantities of a salt and water, and vice versa of determining the proportions of both salt and water necessary to produce a given specific gravity. Thus taking the case of sugar,-what will be the specific gravity of a solution containing equal parts of sugar and water? The volume of the water will, of course, be 1, the volume

The volumenometer employed differed from that used by Holker, in that it had a tubulure in its side for introduction of salt, fitted with a ground-glass stopper. This admitted of the stem being of smaller diameter, and enabled the experiments to be attended with greater Unfortunately, however, the experimenters, whilst acknowledging the disturbing effects of temperature and dilution, seem to have adopted no systematic method of procedure as to the one or the other, unless it be true that the particular temperatures and dilutions adopted of the sugars the total volume being 1-6218. Dividwere selected because the results so obtained accorded ing the total weight 2 by this, we get the specific best with certain theories sought to be established. This gravity 1-23. According to the table in Watts' DicProfessor Marignac evidently points at, though he does tionary,' the specific gravity of a solution containing 50 not actually affirm it. per cent. of sugar is 1-2166 at the temperature 63.5°. Proceeding in the same way with chloride of sodium, we get for a solution containing 20 per cent. of salt the theoretical number 1·159, the experimental number being 1:1511.

I may mention the case of sugar as being especially interesting to the pharmaceutist. The volume occupied by an equivalent of this substance=172 grs., varies according to dilution between 99.00 and 108-06 grm., as follows:

=

1

=

Sulphate of magnesia gives for a 30 per cent. solution

1.172 theoretically, 1·1536 experimentally, the temperature in the latter case being 72-4° instead of 60°, which accounts, doubtless, for the comparatively large discrepancy. A solution of specific gravity 172 would, at that temperature, contain 33.5 per cent. of salt.

To determine the necessary proportions of salt, or other soluble substance, and water in order to produce a given specific gravity is not quite so simple. In order to avoid having two unknown quantities, we will assume the quantity of water to be known. Let it be 10. It is required to ascertain the quantity of sugar necessary to produce with that amount of water a syrup having the specific gravity 1.20. The specific gravity of the water is, of course, 1:00: the specific gravity in watery solution of sugar 1608. The symbol x represents the unknown quantity we have to ascertain. Then

i. e. to produce a syrup of specific gravity 1-20, 789 parts of sugar must be added to every 10 parts of water. Such a syrup ought theoretically to contain 44.1 per cent; at 60°. According to the table in Watts' Dictionary, a syrup of specific gravity 1-2057 at the temperature 63 5 should contain 45 per cent. of cane sugar.

The theoretical considerations involved in the phenomena of solution are so numerous and interesting, that I propose some day to resume the subject I have now merely scratched on the surface, as it were; in which case I will ask again to be permitted to bring the subject before the notice of the Pharmaceutical Conference.

The CHAIRMAN said that this was a very interesting paper, and confirmed some of the views he held on the same subject.

PRESERVATION OF MEAT.

which half the juice and half the water had been expressed, and also about half the soluble albumen and other constituents contained in the ordinary extract of meat, so that the residual pressed meat was actually richer in nutritive constituents than the original meat. If this pressed meat were submitted to further drying by heat, it might be reduced to a state in which it would contain about 10 per cent. of moisture, and meat in that state would keep for almost any length of time. He had hoped that he might have had some samples sent down in order to let the members see what could be done with these products. There were three products-the dry beef, the prepared beef-juice and the ordinary Liebig's extract.

The CHAIRMAN said he thought that the system of preserving meat explained by Dr. Paul, if it would really keep a long time, was likely to be a very valuable one. It was supposed that Liebig's extract, of which so much was sold, was really a feeding commodity, whereas it was not so, but it acted as theine acted in tea,-it prevented waste of tissue, and consequently was rather stimulating than nutritious. But in the plan referred to by Dr. Paul, where you have still 50 per cent. of the extractum carnis, combined with all the nutritive ingreof a true animal food. dients of the meat, the product has more the character

Mr. HANBURY (London) said that this reminded him of a subject which was brought up at a meeting of the Royal Society of London a few weeks ago, when Dr. Simpson took occasion to remark that at a large London hospital with which he was connected the beef tea was prepared so as to contain almost the whole of the solid matter of the meat. The beef was first infused, and then the meat that had been used the previous day, and from which the infusion had been strained off, was reduced to a sort of pulpy state, and mixed with the fresh infusion. It was stated that this plan produced most excellent results, and it had been in vogue for some years, to the general satisfaction of the medical officers and of the patients.

Dr. PAUL, F.C.S., said he was surprised to find himself put down as announced to read a paper on the preservation of meat. He had no intention of doing so, and all he had to give was a merely verbal narrative as to a Mr. DEANE (London) said he had had some experience new method of dealing with meat, which he had recently in regard to Liebig's extract of meat. He found that after had an opportunity of studying. Every one present separating the matter which was soluble in water at a would be aware that in the only successful mode of temperature which would coagulate the albumen, the redealing with South American meat,-in the prepara-sidue was left in a very insoluble and indigestible state. tion of Liebig's extract,-the great mass of the feeding He had come to the conclusion that meat fibre that had portion of the meat was wasted; in fact, instead of pro- been deprived of the phosphates and chlorides that were ducing food, they merely produced a material which held in the juice of the meat among the fibres could be of was a kind of stimulant, the whole of the fibrine and no manner of use, and he should therefore infer that the albumen being lost. Some experiments had been meat prepared by pressure, from which half the soluble made by the inventor of a process to which he would salts had been removed, would be a very indigestible now refer, with the object of drying the meat by pres- substance. Liebig's extract was a restorative under cersure; and he had found, what a great many other people tain conditions, but it would be a mistake to suppose had found who had endeavoured to express from any that it possessed all the nourishment of the meat from organized structure the water or liquid it contained, that which it had been taken. When any of them found he could only succeed very imperfectly. However, Mr. themselves exhausted, it was because the muscular Henley, the inventor of this method, had, by submitting system was deprived of some of its constituents, and it meat to hydraulic pressure, succeeded in removing from was a remarkable fact that when a person was so exit about one-half of the juice contained in the tissue. hausted, if he got a small quantity of Liebig's extract, That juice was a liquid containing the constituents of say half a dram in hot water, in the course of ten minutes the ordinary extract of meat made on Liebig's plan of a wonderful restoration took place. He had a suspicion infusing the meat in water, and it also contained all the that if they had the pressed meat referred to, with half soluble albumen. Its specific gravity, as it ran from of the matter removed, it would be ill for weak stomachs the hydraulic press, was about 1030, and it yielded on like his own, which required a little more of the extract. evaporation about 8 per cent. of a perfectly dry residue. These were the chief points which he had to mention. Of that residue, five parts out of the eight were albumen; He had paid a great deal of attention to the process, and and if the juice were heated up to about 100°, to coagu- he had instructed a gentleman who went out to the late the albumen, they got a pale liquid which might be Australian Meat Company as to the proper method of boiled down, and then gave as residue the ordinary extract preparing the extract. That gentleman went and carried of meat. Another plan of dealing with this expressed out his (Mr. Deane's) instructions very generally, and juice was to evaporate it at such a heat as would not the result had been very successful. In regard to cookcoagulate the albumen, and adding a small quantity of ing, there was no necessity for boiling meat or fish ragelatine: it could then be converted into portable soup, pidly; for if a little time were allowed there would be put into bladders and preserved in that condition for a better results. great length of time. But the principal object of the process was to deal with the residual pressed meat, from

Mr. SAVAGE (Brighton) said that this subject had been under consideration for the Sussex County Hospital. The

extract of meat had been used there, and it seemed to answer uncommonly well.

more the case with salt junk. He thought that this new method of dealing with meat was one worth attention and observation, whatever might be the actual nature of the results.

PROTECTION TO BOTTLERS.

Professor ALLEN said he could endorse the remarks that had been made as to Liebig's extract being a stimulant. He had taken it in a glass of wine and it had a restorative effect. Some people objected to the flavour of it, and some said it had a burnt taste. He could not say that it had that taste; but he used plenty of pepper Mr. BAILDON (Edinburgh) then exhibited a guard to with it. He thought that the preparation of meat sold be put upon bottles, for the protection of men engaged by Fortnum and Mason, Piccadilly, was uniformly pre-in bottling aerated waters. He had no doubt this ingepared. It was in the form of a sausage, which was nious contrivance by Mr. Fraser would be interesting. enough to make a basin of soup. It was a very efficient protection to the bottlers, who often had their hands and arms severely cut. had practical experience of the plan himself, and he could say that it was very simple and afforded very efficient protection.

Mr. ATKINS said he had recently observed one or two striking cases of the nutritive quality of Liebig's extract. He had found that slices of toast covered with Liebig's extract were more effectual as a restorative than anything else he was aware of. He would like to know whether the opposition of the faculty to Liebig's extract was gradually yielding. There was an opinion among medical men that it was deficient in some of the important qualities required in beef-tea.

Mr. MACKAY (Edinburgh) said he could bear testimony to the value of Liebig's extract when made into beef-tea. Several very striking instances of its value had come under his own observation; and, at this moment, there were two persons he had in view who had derived great benefit from it.

One was

a lady advanced in life, and the other a young man, both given up by their medical men, and they were about to sink from sheer want of nourishment. They had taken a dislike to everything that was named to them, and at length it was suggested to them that they should take Liebig's extract, from which they got the greatest advantage. He had often heard medical men speak of the stimulating and nourishing effects of the extract. He had known cases of gentlemen who were out on the moors, and by spreading a biscuit or toast with the extract, it had enabled them to go through almost any amount of fatigue.

Professor WRIGHT said that the prevailing opinion was that the extract did not do so much to prevent muscular waste as to enable the digestive organs to act more perfectly on the food materials and cause less waste than would be the case were the semi-alkaloids not present. Mr. COLLINS (London) said that a friend of his travelling in South America never went out without Liebig's extract; and when he was exploring there was nothing which gave him so much strength. He was sometimes days without any other food whatever.

Mr. SCHWEITZER (Brighton) said he had made some beef powder. It had the same appearance as coagulated albumen, and nothing would soften it.

He had

The Conference adjourned at four o'clock, to mect next day at eleven.

Wednesday, August 2.

The Conference met on Wednesday morning at eleven
o'clock; Mr. STODDART presiding.
Mr. HANBURY read a paper on-

THE CRYSTALLINE PRINCIPLES IN ALOES.
BY DR. F. A. FLÜCKIGER,

Professor of Pharmacy and Pharmacognosy in the
University of Bern.

A large sample of Natal Aloes, a variety of the drugremarkable for its opacity and pale tint has been prosented to me by my friend Daniel Hanbury. Thin fragments of it are so little translucent as to show but a faint brown colour. The fracture of large lumps exhibits a dense conchoidal surface of a dull greyish brown or drab, marked with a few yellowish veins, and quite devoid of the brilliant vitreous gloss exhibited by newly broken Cape aloes.

Fragments freely moistened with spirit of wine, when examined microscopically especially in polarized light, are seen to consist of numerous crystals imbedded in a yellowish amorphous mass which is readily soluble. Mr. Hanbury first observed that the crystals on the other hand are but sparingly soluble and that when the crude drug is treated with spirit of wine they separate as an almost whitish deposit; he consequently suggested they might be something different from aloin. These crystals as they occur in Natal Aloes, are not well defined; most of them are thin, short prisms, sometimes tufted, as in aloin from hepatic Aloes. Sometimes also single, tabu-lar, probably rectangular crystals are met with, as may be seen by gently crushing a fragment of the alocs with glycerine between two glass-slides.

There is no difficulty in separating the crystals from Natal Aloes. If the drug is rubbed with an equal weight or a little less, of spirit of wine at a temperature not exceeding 120° F., the amorphous portion of it is. dissolved. The remaining crystals may be collected on a filter and washed with a small quantity of cold spirit. From 16 to 22 per cent. of crude pale yellow crystals can thus be got.

Dr. PAUL then replied. He said that as to the preparation of Fortnum and Mason, he believed it was a kind of portable soup, made by partial evaporation of beef juice and the addition of a little gelatine. It was not his intention to speak of meat extract as a stimulant. Taking small quantities of extract of meat when a person was working hard might for a time sustain him, but that was no proof that it was food. He might be living on his own body. It was true that the pressed meat was not to be compared with a fresh beefsteak, but that was not the question at all. All meat-preserving methods were intended to utilize a quantity of meat that would The difficulties begin when the purification of the not otherwise be used. It had been pointed out by crystals has to be effected. For this purpose I have tried Liebig that one of the greatest defects in preparing the usual solvents without discovering any liquid that is. his extract was that it left the great mass of the animal thoroughly convenient for dissolving my Natalin, for utterly worthless. It required thirty pounds of beef on by this name I propose to designate the substance. the average, and of the better parts, to produce one pound Neither water, benzol, bisulphide of carbon, petroleumof the extract, and the other twenty-nine pounds were ether, chloroform, or ether, is capable of dissolving natentirely waste. The real way of considering the method aloin in appreciable quantity. A mixture of ether (1 part) he had brought under their notice was to compare it and spirit of wine (3 parts) succeeds a little better; the with the other methods intended to attain a similar re- same may be said with regard to anhydrous aceton, mesult. It might well be that since the pressed meat con-thylic and amylic alcohol, glacial acetic acid and acetic tained less of the juices than fresh meat, it might be less ether. After all however, I do not feel convinced of the digestible and less valuable as food, but that was still advantage of any one of those solvents over common.

spirit of wine, of which 70 parts dissolve at about 60° F., but two of their angles are usually more or less trunone part of nataloin, or of the above-named mixture of cated (B). The amount of truncation of the angles is ether and spirit, 60 parts; while of methylic alcohol 35 usually not the same on both sides (C), and is even someparts, of acetic ether 50 parts, of ether 1236 parts and of times restricted to one only (D). Crystals having all absolute alcohol 230 parts, are respectively required for their four angles truncated are rarely met with (E), and dissolving one part of nataloïn.* pointed scales like F are still more exceptional.

Nataloin in small crystals is rather more intensely yellow than flowers of sulphur; larger crystals display a somewhat orange tint. Its taste is pure bitter, neither a sweetish nor an acrid after-taste being observable. In warm or hot spirit of wine nataloin is scarcely more soluble than in cold. By heating the liquid even gently, it quickly turns darker, assuming a red colour, so that some decomposition is evident, nor can it be wholly avoided by evaporation in vacuo. The best method of recrystallizing seems to be that of heating the nataloïn with 60 or 70 parts of spirit of wine to 100120° F., and allowing the solution thus obtained to evaporate spontaneously during several weeks; in this way may be got crystals of to a millimetre long.

The crystallographic features of nataloïn are very characteristic. The small, first-deposited crystals as well as the larger ones, always consist of extremely thin and brittle scales, not resembling the crystals originally found in the drug. The most perfectly developed crystals of nataloïn are square, or at least rectangular scales (A),

Nataloin which has been quickly deposited from a warm alcoholic solution shows a predominance of the form indicated in fig. G, and sometimes also in fig. H which is striated lengthwise. The latter seems therefore to be rather a combined figure than an individual crystal.

If the scales H are examined in polarized light, the two parts namely a be and a de are sometimes manifestly different in the direction of their refracting power, which in nataloïn is always very brilliant. Finally there are also found irregularly developed crystals (J).

The crystals of pure nataloïn being usually so small, their angles can only be measured approximatively by means of the micro-goniometer. Some estimations not quite satisfactorily ascertained, furnished me 82° for the angle a and 139° for angle b. The crystals are easily broken according to their longitudinal direction, a e for instance in fig. H, yet still more so in a direction parallel to their surface. If an alcoholic solution evaporates very slowly, tabular crystals of appreciable thickness can be obtained, yet in a less pure state. If they happen to be a little injured, their longitudinal edges exhibit a distinct lamellar structure as shown in fig. K. Crystals of this kind are chiefly formed from a solution in acetic ether. An alcoholic solution yields mostly regular square scales.

Nataloin gives off no water when exposed over concentrated sulphuric acid or when heated to 212° F., in either case even for some days; and this behaviour shows at once that it is not identical with the aloïn discovered by Messrs. Smith of Edinburgh and examined by Dr. Stenhouse. According to this chemist, crystallized aloïn parts with 2.69 per cent. of water when dried over sulphuric acid, and entirely loses its crystalline aspect when kept for some days over a waterbath. Nataloin is not even altered or its weight diminished if it is heated to 284° F. Decomposition begins to take place only towards 320° F. when the nataloïn turns greyish; the temperature named having been maintained for many hours, the loss of weight amounted only to 3.8 per cent. At 356° to 374° F., nataloïn fuses becoming previously of a dark, brown red, but it is still partially crystallizable as may be ascertained by treating it with solvents.

Nataloin is soluble in concentrated sulphuric acid; the orange liquid yields a precipitate by addition of a small quantity of water, but the dingy colour of the nataloïn so obtained probably shows that partial alteration has taken place. If the vapour of fuming nitric acid is cautiously directed on to a solution of nataloïn in sulphuric acid, the latter acquires a fine green colour, quickly changing to red and blue. This very intense and distinctive reaction which was first pointed out by Mr. Histed, may be illustrated as well by rolling a crystal of saltpetre in the sulphuric solution. A small grain of chlorate of potassium produces a brilliant green zone, almost instantaneously disappearing. Nitrate of bismuth gives nearly the same effect. Bichromate of potassium acts in a similar manner as with strychnine only that the colour is less pure. Natal aloes being so rich in nataloïn, itself displays these reactions by which in fact, it may be easily distinguished from the aloes of the Cape, Zanzibar or Barbados,

By heating nataloïn with nitric acid of about sp. gr. 1-3, to 140°-160° F., a red solution is obtained which at length turns yellowish as the nataloïn slowly disappears. But I have not been able to discover in this liquid either picric or chrysamminic acid, yet the latter according to

This however may quite as well be due to the occasional superposition of extremely thin scales.