the stomach ? If it is the product of the lactic acid, which is mixed with sea salt? If it is the product of hydrochloric acid, which is mixed with a lactate?

In my opinion, the acid which is formed is the lactic. Meanwhile, this acid, when placed in contact with sea salt, forms a mixture which may in certain instances present the properties of hydrochloric acid. The solution which I give of the first question is supported, it is true, by no positive fact, except that of the experiment itself. There is always more acid than is necessary to saturate the base, and in all instances we find we isolate an acid which possesses all the properties of lactic acid, and which does not render turbid the salts of silver. This lactic acid is formed elsewhere in the economy. It proceeds from the fermentation of sugar; and the experiments performed in common by M. Bernard and myself prove that the blood of animals, at least animals with warm blood, uniformly contains sugar, even when it has received no vegetable matter; and nothing appears more simple than to think that this acid is formed at the very moment at which the gastric liquor is secreted, and that, by a fermentation as rapid as that of amygdaline by the emulsine, which, it is known, is formed at the very instant of contact.

There is further an example which I shall borrow from our experiments, and which, if I am not deceived, proves to a certain degree analogically the fact of the formation of acid at the exact moment of secretion. If we cause an animal to swallow urea, or if we inject it into the blood, it is absorbed, and it is without alteration added to that which is normally found within the bladder.

This fact being established, if we remove the kidneys from an animal, if we thereby induce suppression of the secretion of urine (and we are indebted to MM. Prevost and Dumas for this experiment, which M. Bernard and I subsequently repeated, and made the subject of comment), we observe that urea is accumulated in the blood; but how considerable soever be the proportion which we can extract from the blood, this is far from accounting for the quantity produced. Now if we inquire by what channel, when the kidneys are removed, the urea may escape from the combination, we find that it is by the stomach, which indeed is filled with liquid. But the urea, which, while in the blood is in the state of urea, is found in this liquid contained in the stomach in the form of ammoniacal salts; it results then that the transformation of the urea takes place at the exact moment of secretion.

The second proposition is the following: Admitting that the gastric juice is acid, because lactic acid is added to it, is it to this acid or to the hydrochloric acid which it eliminates that the pro

perties of the gastric liquid are owing? To this I reply, that it is of little moment, considering that the experiments of M. Bernard and myself have proved that all the feeble acids behave in an analogous manner.

But I thought it possible to enter further into the question. I think that the following experiment throws some light,—I shall not say certain, but probable,-upon the hypothesis, that it is lactic acid, and not hydrochloric acid, which is in a free state in the gastric liquid.

M. Payen has shown that starch, which is so easily converted into sugar by the mineral acids, even in a diluted state, does not undergo this conversion by the action of the organic acids. Upon this experiment I support my proposition. I made of hydrochloric acid of commerce from three to four drops in ten centimes; I then placed separate portions of the solution in two tubes. To the solution in one tube I added sea-salt; to that in the other, acetate of soda; and into both I poured very clear paste in equal quantity; and both I maintained for twenty minutes at the temperature of from 38 to 40 degrees 100-2° and 104° Fahrenheit. At the end of this time I observed that the starch no longer gave a blue colour to iodine in the tube which contained sea-salt, while it did give a blue tint to the portion contained in the tube with the acetate of soda. From this experiment I concluded that the hydrochloric acid was free in the first tube, while in the second it was combined with soda in substitution of the acetic acid, which was alone free in the liquor.

5. Causes of the Disappearance of the Sugar of the Egg.—I have in all instances found sugar in the egg. I have not had the means of operating upon the eggs of the carnivorous birds; and the trials which have been made to obtain eggs from fowls fed exclusively on animal food have given no result. This idea, nevertheless, I have not abandoned, and I trust to return to it.

I shall not then speak here of the case in which sugar is naturally wanting; but of its disappearance as shown by experiment. I have said above, that when we seek for sugar in the residue of the evaporation of the mother-liquor of coagulated albumen, we find it not, or we meet only with minute quantities of it. I have intimated that the destruction of sugar ought to be ascribed to the simultaneous presence of carbonate of soda and air. Indeed, direct experiment has taught this fact; the sugar of starch disappears by the action of the air, under the influence of alkalis. This fact is very important; it proves how in one analysis two products may disappear in mutually destroying each other, and how we may meet with principles which are not previously present, and which are formed even in the course of the operation; finally, it explains, I think, differences noticed

among the experiments of different chemists upon the presence of an alkali in the blood.

Sugar may undergo a fermentation,-a spontaneous destruction. When white of egg is exposed to the air, it disappears so much more rapidly, as it is more diluted; should we ascribe this phenomenon to the presence of air? I think not. In truth, the egg, even within its shell, receives the impression of the atmosphere. It is requisite, above all, to pay attention to the state of dilution; for, I repeat, the fermentation which takes place slowly in albumen in the natural state, is infinitely more rapid in albumen of egg diluted with water. I could cite several examples of analogous instances, in which fermentation is favoured by dilution. Thus, for example, the water of gooseberries sugared ferments on the second day; while confections of gooseberries, which differ from the water only by concentration, are preserved from one year to another.

These confections, nevertheless, do not in all instances remain unalterable; and the mode of their alteration, if it be closely observed, is a proof of the influence of dilution. When confections of this kind are left in a place at once warm and saturated with moisture, their surface very soon becomes liquid, and gradually the entire mass is liquefied more and more rapidly; and the alteration, though slow in evincing its presence, advances with extreme velocity. This phenomenon is owing to this circumstance, that in proportion as the alteration manifests itself, the posture of the confection being modified, is converted into a matter, which retains less water in combination (metapectic acid), and because thus consequently the water is set at liberty, modifies the portions of the confections not altered, and thus accelerates the metamorphosis.

This effect is only remarked in a place constantly moist; otherwise, in ordinary circumstances, the paper and the sugar which covers the confections, is sufficient to remedy, by their hygrometrical properties, the alternations of moisture and dryness.

The influence of dilution being, I believe, undisputed, it remains to determine the mode in which it acts. Is its object simply to allow the air to circulate more casily in the liquid, or does it not happen, that by the mere single fact of concentration, the ferment, or the substance which is to produce it, is insoluble in the vehicle, unless it is diluted with water, and, by the sole circumstance of its insolubility, is protected from all decomposition? This question is invested with high importance, especially in the study of the chemical phenomena of life; and I have accordingly endeavoured to resolve it. Among a great number of experiments made with this object, I shall describe the following, which to me appear to afford a satisfactory solution.

If we bray in contact with the air a moist almond and some sugar in powder, with a sufficient quantity of water to render the mixture fluid, but not to dissolve all the sugar, and if to this liquor be added amygdaline, continuing the operation of braying, we obtain not the odour of the bitter almond, which is developed in the contact of the emulsine and the amygdaline, and yet we operate with the air in contact and incessantly renewed by the braying. The phenomenon being established as a fact, we may cause the development of the odour with the greatest energy, by adding pure cold water, that is, by diluting the mixture.

I have selected as an example sugar, because it is employed by every one. I might have employed other reagents; I should have equally been able to put in play another ferment, and another fermentable substance. Thus, I have ascertained that all the ferments and the organic matters of the number of those specified by M. Colin, as giving rise to ferments, especially to the alkoholic ferment, are in this situation.

Albumen appeared to form an exception. It is in truth not precipitable in its solution by sea salt, even when in great excess. This circumstance was very unpleasant; and it might even to a certain extent be turned as an argument against me, by stating as an objection the preservation of animal food by salt. But I very soon saw that this anomaly was only apparent. If indeed it is true that albumen in its ordinary state is not precipitated by sea salt, it is sufficient to cause it to undergo a slight modification, in order that it become precipitable. All that is required is to saturate its alkali by a trace of vinegar or of lactic acid; for this circumstance is exactly that which is always presented. It is well demonstrated that the first degree of putrefaction in albuminous solutions, such as soup, is evinced by the presence of acescence. We must not, however, confound this precipitation of albumen with the coagulation effected by fire or by alkohol. In truth, the coagulated matter formed is soluble in water. This anomaly, which albumen exhibits in the presence of sea salt, is no longer found in the presence of other precipitating agents. Thus, for example, the sulphate of soda precipitates albumen when the albumen is alkaline; the same salt precipitates not only the ferments, but gelatine, starch, and gum.

When we repeat the experiment of the precipitation of albumen by means of sulphate of soda, it is proper to observe a precaution in order to obtain a result which may leave no sort of doubt. This is to maintain the albumen at a temperature of about 33 degrees 91-2° Fahrenheit, the maximum of the solubility of sulphate of soda. On this side of, and beyond this limit, the precipitation is no longer complete; so that the solution of albumen, fully saturated with salt at 20 degrees, becomes turbid when

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M. Francois on Idiopathic Convulsions of the Face. the temperature is carried to 33 degrees, =91°, 2 Fahr., but becomes afterwards clear when this limit is passed. This experiment is one of remarkable exactness. It ought to be taken into consideration in the analysis of the blood. Direct trials have proved to me that the globules were not the only matter eliminated. I shall, however, return to this question; and I shall show, I hope, in what manner we may, by the assistance of dilution, or of concentration respectively, ensure the departure of certain principles of the blood, either in an isolated manner, or by a series of analogues.

In conclusion, I conceive that I have, in the preceding observations, established the truth of the following propositions :

1. That sugar exists in the white of the egg of the common fowl.

2. That the white of egg is alkaline; and that its alkalinity is owing to carbonate of soda.

3. That the yolk of the egg contains no alkali, and that its emulsive property belongs to a product analogous to that of the pancreatic liquid.

4. That the yolk is not acid, and that it becomes so in consequence of alteration.

5. That (by depression) the acid reaction, and the properties of the gastric liquid, are owing to an organic acid, and not to hydrochloric acid.

6. That the alkali and the sugar of white of egg might disappear by destroying each other in the experiment of demonstration, and thus explain the discordance in the results obtained by different methods of experiment.

7. Lastly, That the alteration of the albumen of egg, and of all analogous matters, is so much more rapid, in proportion as these matters are in a more diluted state; and that the cause of the greater or less rapidity in alteration is owing, all other circumstances being equal, to conditions which, more or less, favour the solubility of the ferment.

ART. VII.-Essay on Idiopathic Convulsions of the Face. By M. V. FRANCOIS, Titular Member of the Royal Academy of Medicine of Belgium. [Memoirs of the Royal Academy of Medicine, Belgium. Volume First. Brussels, 1848. P.23. Part Second, and Conclusion.] (Abstract.)

SINCE I communicated to the Academy the first part of this memoir, imperfect as it is, in the course of a visit which I made to London at the close of September 1847, I procured the work

VOL LXXV. No. 187.

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