a Prize Thesis 'On the Origin of the Hippuric Acid in the Urine of the Herbivora,' which, however, is chiefly valuable for its negative results. He distinctly proves by a long series of carefully-conducted experiments and analyses, that the natural food of the Herbivora contains no benzoyl-compound (in the ordinary acceptation. of the term), which would account for the formation of the hippuric acid, and thus establishes (as the adjudicators of the prize believe) the fact that the production of this acid is due not to any peculiarity of the food, but to some special mode to which their metamorphosis of tissue proceeds, probably to the slowness of this action as compared with the rapid destruction of the tissues in the carnivora.

Weismann, who competed with Hallwachs for the prize offered by the Medical Faculty of Georgia Augusta, and to whom a prize was likewise awarded, has also published his Thesis. The main point of his essay is to show that the formation of hippuric acid is due to the nature of the food, and that lignin is its most probable source, a view to which little weight can, we think, be attached. We extract the following remarks on the influence of the food on the amount of hippuric acid excreted daily by himself:

"On a mixed diet my urine contained on an average (the mean of twenty-six observations) 0145 per cent. of hippuric acid, and the quantity excreted in twenty-four hours averaged 2:473 grammes.

"On a purely animal diet my urine contained on an average (mean of eight observations) 0-080 per cent, of hippuric acid; the mean daily quantity was only 0·765 of a gramme, and the amount fell after one day's animal diet to 0.798 of a gramme, the quantity on the previous day having been 1808 grammes; and during the three days on which the purely animal diet was maintained the numbers were 0.798 of a gramme (on the first day), 0·723 of a gramme (on the second day), and 0-775 of a gramme (on the third day), so that there was no reason to believe that they would further diminish if the animal diet were longer continued.

"On a bread diet, on which I subsisted for seven days, taking only bread and water, my urine contained on an average C070 per cent. of hippuric acid, and here also soon sunk to a fixed limit, beyond which it did not fall during the continuance of this diet.

"In order to convince myself with certainty that no constituents of vegetable food retained in the body could have given rise to the formation of the hippuric acid during the above experiments on a purely animal and a purely bread diet, I frequently analysed the urine of typhus-patients, who for two to four weeks had taken nothing but milk and bouillon, and invariably found it to contain hippuric acid. The urine of these patients contained on an average (the mean of twelve observations on seven patients), 0·050 per cent. of hippuric acid."

Dr. Thudichum's next chapter is devoted to the consideration of chlorine and the chlorides. We extract the following remarks on the quantity of chlorine that is daily excreted by healthy persons under different physiological conditions:

"That the amount of chlorine discharged during twenty-four hours varies in different individuals, undoubtedly depends mainly upon the fact, that unequal amounts of chloride of sodium are ingested with the food of different persons. Sailors who have lived on salt rations for the greater part of their life spent afloat, will discharge an extraordinary amount of chlorine in their urine, because the ordinary food of our kitchen is insipid to them without the addition of an amount of salt that would make any ordinary person ill . . . . The amount of chlorine discharged by an individual varies on different days according to and corresponding with the amount of chloride of sodium taken with his food. When Falck ate strongly salt food on three successive days, he discharged the following respective amounts of chlorine-viz., 60, 7·8, and 10-3 grammes during twenty-four hours. But when he partook of food containing no addition of salt, he discharged 2·5, 1·6, and 0·9 grammes of chlorine on the three respective days succeeding the experiment. Professor Vogel observed the amount of chlorine discharged per hour by several individuals who had taken kitchen salt in doses not sufficiently large to purge them. In all the amount of chlorine discharged per hour was increased and rose from 04 to 1.0, nay, even 18 grammes."

As a general rule, it appears, from the researches of Hegar and others, that the urine is richest in chlorine a few hours after the largest meal of the day, and poor

⚫ Ueber den Ursprung der Hippursäure im Harn der Pflanzenfresser.

Preisschrift. Göttingen, 1857.

est during the period of sleep; and further, that mental and bodily activity will increase the secretory activity for chlorine of the kidneys at any time during the day or night. Vogel has, however, shown, that by the ingestion into the system of large quantities of water, the amount of chlorine (like that of urine and urea) is increased.

Since the time of Redtenbacher's well-known discovery of the temporary disappearance of the chlorides in pneumonia, many observers have carefully noted the variations of these salts in various forms of disease.

"The result (says our author) of many observations of Vogel and others, last of myself, is, that in all acute febrile diseases the amount of chlorine discharged in the urine sinks rapidly to a minimum, say one-hundredth part of the quantity normal to the individual, until at last in certain cases it disappears entirely for a short time. When the diseased action is abating, the amount of the chlorides rises during convalescence, sometimes above the normal average. We have already seen that the total quantity of urine has a similar relation to the stages of acute febrile diseases. But it is the reverse with the colouring matter or uræmatine, the amount of which rises and falls in the inverse ratio of the chlorine; so that when the latter is entirely absent, the former is discharged in the largest quantity. Urea, on the other hand, though rising at first in amount inversely to the sinking of the amount of chlorine, afterwards sinks below the healthy average, and during convalescence rises parallel with the amount of chlorine."

The following instance will show what variations may be expected in similar cases. In a man with severe pleuro-pneumonia, Vogel found that the total quantity of chlorine sunk to 0.6 gramme on the third day, to 0.3 gramme on the fourth, and on the fifth to almost nothing. From this date an improvement took place, and the chlorine rose on the succeeding days to 0'4, 18, 26, 5·5, 9′0, and 10·7 grammes, the latter being about the normal average.

Bronchitis, typhus, acute rheumatism, pyæmia, and pleurisy, are, in addition to pneumonia, diseases in which this variation of the chlorides has been especially noticed. In chronic diseases the excretion of chlorine is generally diminished, as might be expected from the bad nutrition, and generally poor appetite of patients of this class. Diabetes insipidus forms, however, an exception to this rule. In a case of this nature, Vogel found the amount of chlorine discharged by the urine to be occasionally increased to 29'0 grammes. The same excellent observer found that dropsical patients, under the influence of diuretics, discharged an increased quantity of chlorine, which must have passed (dissolved in the exudations, &c.) into the tissues and cavities. In dropsical or hydræmic cases an increase of the chlorides in the urine is a favourable symptom.

There is nothing in the chapter on sulphuric acid and the sulphates that need detain us, and we pass on to the consideration of phosphoric acid and the phosphates.

Taking the mean results of the analyses of Breed, Winter, Mosler, Neubauer, and Aubert, our author finds that the average amount of phosphoric acid discharged by an adult male in twenty-four hours is 3.66 grammes; and further, that there is a regular rise and fall in the hourly amount of phosphoric acid, the rise invariably taking place soon after the principal meal of the day. The maximum secretion was observed during the hours of the evening, the quantity falling during the night, and being at the minimum in the morning.

As the internal use of sulphur, sulphurets, sulphuric acid, and sulphates increases the quantity of sulphuric acid in the urine, so we find that the introduction into the body of phosphorus, either in the form of the acid, or of phosphates, or in combination with albuminous substances, gave rise to an increase of the phosphoric acid in the urine. It has been ascertained that total abstinence from food, or from food containing phosphorus, diminishes the amount of phosphoric acid, but does not cause its entire disappearance, the small persistent portion being probably due to the continuous oxidation of albuminous tissues.

The results regarding the quantity of phosphoric acid in the urine in disease, as

determined by Vogel from more than one thousand observations, may be summed up in the following sentences:

"In acute but not very severe diseases the amount of phosphoric acid in the urine decreases at first most probably in consequence of the low diet, and afterwards rises again with a more liberal allowance of food. During convalescence, the normal amount is sometimes exceeded in consequence of an increased quantity of food.

"If the illness, though combined with violent fever, only lasts for a short time, the decrease of the phosphoric acid is sometimes very slight, and scarcely perceptible.

"When the diseases are of a more severe nature, so as to cause a long abstinence from food, or to take a fatal turn, the decrease of the phosphoric acid in the urine becomes much more considerable.

"In some exceptional cases the amount of phosphoric acid discharged during the height of acute diseases may considerably exceed the amount discharged during health.

"In chronic diseases the excretion of phosphoric acid takes a very irregular course, and though remaining mostly below the normal average, may sometimes considerably exceed it."

There is nothing calling for any special remark in the two succeeding chapters on "The Free Acid of the Urine," and on "Potash and Soda.”

The next chapter, on "Lime and Magnesia," includes the consideration of Deposits of Earthy Phosphates. We extract the following sentences in reference to this important subject:

"As a rule, deposits of earthy phosphates can exist only in urines exerting an alkaline reaction upon test-paper. There is only one (questionable) case in which.a deposit of an earthy phosphate is compatible with an acid reaction of the urine-namely, when urine containing little or no free acid exerts an acid reaction from the presence of chloride of ammonium. In this case a deposit of phosphate of magnesia may perhaps exist, for the salt is little or not soluble in chloride of ammonium. But phosphate of lime is so soluble in the latter salt that it could not exist as a deposit so long as any acidity of the chloride of ammonium is not neutralized. The observations which are said to have been made of urine having an acid reaction and yet containing a permanent deposit of phosphates (see Dr. G. Bird's Urinary Deposits,' p. 260, § 261), if they cannot be explained in the way just detailed, must be considered as fallacious. They are contrary to the commonest law of chemistry. I have made some observations which may serve to explain the manner in which such statements have come to be called observations. Clear acid urine was allowed to stand for three hours, when a pellicle of phosphates was observed on the surface. Blue test-paper, immersed an inch deep into the fluid, on being withdrawn, had become red. Another piece of the blue test-paper was now laid flat upon the surface of the fluid, when no reaction took place. The upper stratum of the urine had evidently become alkaline under the influence of the air, while the lower strata had retained their acidity."

The quantity of earthy phosphates normally discharged by the urine in twentyfour hours, has been determined by several observers. Beneke fixes it at 1.2 gramme for a healthy man; while Lehmann found that he discharged 1·09, and Böcker 1:48 grammes. We cannot, however, give any fixed average, as the quantity depends upon the amount of earthy matter taken in the food, and not discharged with the feces.

Our author lays down the following general rules regarding the pathological indications afforded by the presence of these deposits:

1. "The presence of earthy phosphates in the urine is indicative of the alkaline condition of that fluid."

2. "If the precipitate of earthy phosphates is entirely amorphous, we may conclude that the alkali which formed it was not ammonia."

3. "If, however, the precipitate contains crystals of triple phosphate, it indicates the presence of ammonia, arising most probably from the decomposition of urea.'

It has been long known that animal diet has a tendency to increase the acidity of the urine, while vegetable diet acts in the opposite manner. Dr. Thudichum lays great stress on this fact. The alkaline urine often noticed in aged paupers is, or may be, the consequence of a deficient supply of animal food, and we can very generally render their urine again acid by a proper allowance of meat. A similar

treatment may often be successfully adopted in anæmia-a disease in which we usually find a deficiency of the free acid of the urine.

Passing over several chapters, we arrive at the consideration of albumen. Our author observes, that "when albumen is digested with permanganate of potash, urea is obtained as one of the products of oxidation ;" and in his chapter on fibrine, he observes, that "Béchamp has produced urea from fibrin by oxidising agents, so that the ultimate fate of fibrine appears to be determined." We are sorry to be compelled to state that Städeler has very recently overthrown Béchamp's supposed discovery, and has shown (we fear, beyond a doubt) that he mistook benzoic acid, which would naturally be formed during the experiments, for urea. We regret that our limited space compels us to omit any notice of the section on the "pathological indications of albumen," which concludes this chapter. The chapter on Grape-sugar is followed by one on Acetone, which has lately been discovered in the urine, blood, and most parts of the body of a diabetic patient. It is possible that the peculiar odour so frequently noticed in diabetic urine is due to the presence of small quantities of this substance. The suggestion that the odorous substance in question was acetone, is due to Dr. Lerch; the determination of it was made by Petters.

Many of our readers are probably not aware that indican, a gum-like vegetable substance, which when boiled with acids yields indigo blue, seems from the researches of Schunck and others to be generally present in small quantity in healthy human urine. The urines of forty different individuals, all of whom were apparently in a good state of health, yielded, with a single exception, more or less indigo blue. The persons in question were of both sexes, and their ages varied from seven to fifty-five; and diet seemed to produce no definite effect upon the quantity of indigo blue that occurred. The urine of the horse and cow (especially of the horse) gave comparatively very large quantities of this substance. It does not seem (from the recent investigations of Virchow) that the presence of this substance even in some excess, is indicative of any peculiar morbid state; concentration being apparently the main condition upon which its detection depends. It was formerly believed to be specially associated with albuminuria.

The chapter on "Oxalic acid" contains many original observations on various points connected with the physical and chemical characters of the different crystalline forms which we generally consider to pertain to oxalate of lime, and is well worthy of a careful perusal.

The volume concludes with a full consideration of what our author terms urophanic substances those substances, namely, which pass through the body and reappear in the urine without undergoing decomposition. We shall take as our final extract, our author's remarks on the passage of strychnine into the urine, and the method to be employed for its detection.

The

"Strychnine when introduced into the animal economy in any notable quantity-for example, in the ordinary medical doses at from one-tenth to one-twentieth of a grain, repeated at intervals, reappears in the urine. In order to obtain strychnine from urine, it is only necessary to evaporate the fluid to the consistence of a thin syrup, to make it strongly alkaline by caustic potassa, and to shake it with large and repeated quantities of ether. ethereal solution, which is only obtained after some standing, and sometimes only after the addition of some alcohol, is evaporated, and the residue treated with concentrated sulphuric acid on the water-bath. After several hours' digestion, the acid is neutralized by carbonate of soda, the fluid is then made alkaline, and again extracted with ether, which after evaporation will leave strychnine, to be tested by the taste, and by the reaction with bichromate of potassa and sulphuric acid. The latter reaction is best effected in the following manner. The solution in water of the supposed alkaloid is placed in a small china dish, and after evaporation to dryness at a low temperature, is dissolved in a drop or several drops of sulphuric acid. The solution is now spread over the space of about a fourpenny piece. A small granule of bichromate of potash is now dropped into the solution. On moving the fluid by giving the china dish different inclinations, violet streaks are perceived to flow from the granule of bichromate, and on moving the crystals to and fro in the fluid by means of a glass rod, the entire solution soon assumes a fine purple colour (Otto).

"One grain of a solution of strychnine, containing one forty-thousandth part of a grain of solid strychnine, yielded this test quite clearly. Five drops of the same solution brought upon the tongue, had a decidedly bitter taste; on some occasions, two or three drops would permit the bitterness to be recognised."

We ought to mention that the volumetric methods of testing for the various substances occurring in the urine, are very fully given in this volume: they are as yet little known or practised in this country, although in many cases they present great advantages over the ordinary modes of analysis.

When a new edition is called for, which we doubt not will soon be the case, we would suggest a revision of the references given in the foot-notes. Thus in pp. 15 and 77, there are notes referring to previously quoted works of Vogel and Gerhardt, yet where these works are previously quoted we cannot ascertain. There are also a few words occasionally met with which have as yet hardly established themselves in the English language, as for instance hydrothion, in p. 299, a substance familiar to our readers under the term of sulphuretted hydrogen. These are, however, very slight drawbacks, and upon the whole we may award our author great praise for his very painstaking and elaborate work. It is a perfect encyclopædia of all matters connected with the urine.

We regret that we cannot speak in equally favourable terms of the new edition of Dr. Golding Bird's "Urinary Deposits," edited by Dr. Birkett. While there is a considerable amount of new matter in this edition, there is a great deal of equally important matter of which no notice is taken, while a good deal that had better have been removed is retained.

A considerable amount of trouble and inconvenience arises from the fact that the reader has no means of deciding to whom the authorship of any particular part of the volume is due. By the use of brackets or initials, Dr. Birkett might easily have indicated what his additions really are. Let us turn, by way of illustration, to p. 47. Who is the "old pupil" who bears his humble testimony to the elegant scholarship of Dr. Keate? Is it Dr. Bird or Dr. Birkett? Is it, we ask, fair to leave the reader in doubt on so interesting and important a question? In pp. 94, 95, it is almost impossible to know whose views are being expressed. We seem to have an inexplicable admixture of incongruous views. In the first place, we have a series of analyses of urinary sediments by Dr. Letheby. These analyses are succeeded by the natural remark, "that the deposits usually considered to consist principally of urate of ammonia, are in reality made up of urates of lime, potash, and soda. . . As these views are ingenious" [they are better than ingenious, they have just been proved to be true in the preceding paragraphs], "and are still supported by some chemists, I have hesitated to remove them, though myself persuaded of their fallacy. I believe that the explanation of the proximate formation of these deposits is to be found in the action of uric acid on the microcosmic salt or double phosphate of soda and ammonia." If our readers can extract any clear ideas as to who is persuaded of the fallacy alluded to in the foregoing sentence, and why any one should hold views directly based on Dr. Letheby's analyses to be fallacious, they will deserve credit for their ingenuity. Were we inclined to be hypercritical, we might object to the editor's allowing Dr. Bird's remark in p. 105, that lactic acid exists in the sweat, to remain uncorrected. Schottin, who worked under Lehmann's direct observation, ascertained that no lactic acid occurred in that excretion either in health or in disease. why is Pelouze's fallacious test for lactic acid still given? Ten years ago, or more, Pelouze himself showed that it was not to be depended on. Again, in p. 112, we find Dr. Kemp's analysis of the organic material of human bile quoted and contrasted with analyses of hippuric acid and urinary colouring matter. Does not the discovery (and it is by no means a recent discovery) of sulphur in the bile altogether do away with the value of such comparisons?

And

In our perusal of the fourth chapter, On the Pathology of Uric Acid, and its Combinations, we made the singular discovery that the great drainage-system which is spreading itself so widely and rapidly over all our agricultural districts,