heat-making food in a climate where the heat is very great? There is an issue from this dilemma: It is possible that the starch and dextrine of rice are not converted into heat, but only the fat is so converted. I say this is possible; but Liebig has not appealed to such a possibility, for he could only do so by destroy ing the very theory he had to defend. If the starch and dextrine are not heat-makers, then his classification of the carbonaceous substances as heat-makers is at fault, and the part played by starch has to be discovered; if, on the contrary, they are heat-makers, as he assumes, then we must ask why the Hindoo consumes them so largely?

This is only one of the examples selected, but I am content to let the decision rest on it. How is it handled by my critics?

""Moral, religious, and political considerations," says Dr Daubeny, "no less than the natural promptings of appetite, influence the individual and community in the preference for certain articles of food and the rejection of others. If the Hindoo, for instance, lives on rice and butter, it must be recollected that his religious scruples preclude him from the use of animal food." If the kind of food were a question of taste and fancy, I could understand this argument; but inasmuch as physiological laws refuse to obey moral, religious, and political considerations - inasmuch as a religious dogma cannot convert a heat-making substance into one yielding no heat-we must reject this defence altogether, although the Reviewer refers to it with approbation. Liebig affirms the carbonaceous food to serve no other purpose than that of furnishing heat. I pointed to the fact that the Hindoo, who wants considerably less heat than the European, subsists mainly on this heat-making food; whereupon I am told that the "religious observances greatly influence the result." This is the first time I have heard that a chemical fact obeys a theological edict; and that a law of nature changes in obedience to a religious observance.

The Reviewer, after thus explaining away the difficulty presented by

the Hindoo, remarks that the evidence furnished by labourers subsisting mainly on potatoes, and labourers who eat largely of animal food, proves that a greater amount of work can be got out of the latter. But since I have myself (p. 174) very explicitly stated this fact, the Reviewer might have hesitated before adducing it in defence of Liebig. We must say the same of what follows: "And in like manner, when a comparison is made between the experience of individuals or bodies of men exposed to different temperatures, it is found that the diet on which heat can be adequately supported in even the colder temperate climates, needs to be supplemented by an additional proportion of fat, or of some other efficient heat-producing material, to make it fit for the maintenance of the vigorous calorification needed by those who have to endure the rigours of an arctic winter." Now it is difficult to state more explicitly than I have done the "fact that, in cold countries, fat and oil are greedily devoured; and it is the most striking fact that can be adduced in favour of the hypothesis now under discussion." But instead of leaping to the conclusion that this fat must necessarily be demanded for animal heat, and nothing else, I said, "We have yet to learn that fat is simply so much combustible material.' The demand for fat in cold countries may arise out of various conditions." Indeed, it is obvious that until the part actually played by fat is determined, the experience of arctic voyagers can only be an index, not an answer. According to universal experience, cold causes a greater demand for food, and that food animal food. On the chemical theory, this increased demand would not be for nitrogenous food, since that merely supplies the waste of tissues, but for carbonaceous food (or let us say fat only) which can be burned, to supply the needful heat. Now, while it is a fact, well worth considering, that the Esquimaux consume large quantities of fat, and thus countenance the chemical theory, it is no less true that they consume enormous quantities of flesh; and this puts the chemical

theory in embarrassment. While the average European diet may be taken at six or seven pounds daily, the Esquimaux are said to eat twenty pounds of flesh and fat daily. Assuming the correctness of the statement, we must ask two questions: First, is it the greater waste of tissue in the arctic regions which renders this enormous increase of food necessary? If this be so, then we need not be surprised at a larger amount of fat being necessary. Secondly, is it only to supply the increased demand for heat that so much fat is required? If so, then why is not the increase of food confined to the oily substances, and why is the consumption of flesh so enormous? Thus, whichever way we view it, the testimony of arctic voyagers can only be cited in support of the chemical theory, on the condition of fixing attention solely on the fat, neglecting the flesh eaten in quantities so far surpassing the demands of an European. The Reviewer cannot have considered this difficulty, for, after referring to the twenty pounds of flesh and oil daily eaten by the Esquimaux, he says

"That by far the larger proportion of this fat must be burned off,' to use Liebig's phrase, without ever being converted into tissue, we apprehend that every well-informed physiologist must be ready to admit. For let us look what

monstrous assumptions are required by Mr Lewes's doctrine, that no food is applied to the maintenance of heat, until it has been first subjected to the process of tissue-formation, and has been then set free by the waste consequent upon exercise. In the first place, it must be assumed that, by some wonderful process of transformation which Mr Lewes does not attempt to explain, fat to any amount can be turned into muscle. That muscular fibre can be generated at the expense of anything else than albuminoid material, combined with a minute proportion of fat and the requisite salines, we may safely challenge Mr Lewes to prove."

The challenge is a very safe one, no hint of such a proposition having escaped me; nor do I understand how a physiologist so very well-informed as this Reviewer unquestionably is, could have supposed that by "waste of tissue," only muscular tissue was meant. I said that "it is the tissues

which are burned (if burning there be), and not the food itself;" and it is to this cause that animal heat is chiefly due: the Reviewer is therefore not justified in speaking as if muscle were the only tissue, and in asking how fat can be transformed into muscle.

We return, then, to our position; if physiology is embarrassed to say what becomes of the immense amount of fat eaten by an Esquimaux, not less is the embarrassment created by the immense amount of flesh. Supposing all the fat goes to sustain animal heat, what becomes of the surplus flesh? This question will be seen to have a more formidable weight when we learn that, according to the careful and elaborate experiments of Bischoff and Voit, no sooner did the amount of flesh given to their dog reach a certain figure, than the dog ceased to "burn any fat, and supplied the whole of its animal heat from its nitrogenous materials.

It is unnecessary to prolong this controversy. The defenders of Liebig have failed to show that his Method is the right one, and that chemistry alone can successfully deal with vital problems, of which food is one. They have failed to show that the anatomical distinction on which that theory rests is one which an anatomist can admit. They have failed to show that the practice of various nations, and the experience of cattlefeeders, have justified the previsions of the theory. These were the three points on which my batteries were erected; and, until those batteries are silenced, the defence will be in vain.

I will not trespass on the reader's remarks on the views I have put time by any notice of the Reviewer's forth respecting the Nervous System. There is in them so obvious a want of candour, as well as of good hardhitting in the way of valid objection, that anything like rational discussion becomes impossible. Instead of wasting valuable space with such controversy, it will be better to conclude this letter with a glance at the very remarkable work published by Bischoff and his assistant Dr Voit, which professes to place Liebig's theory in a somewhat new light,

while confirming its principles by the most indisputable evidence. It claims to be nothing less than the Laws of Nutrition in Carnivorous Animals established upon New Researches.* Remarkable for the patient care with which its researches have been made and tabulated, this work is also interesting to us as furnishing some of the most conclusive evidence against the very theory it is meant to uphold. What degree of confidence is to be given to its method and calculations, I am unable to say. These will in due time be appreciated by scientific inquirers. For the present I am content to accept as indisputable all its facts and figures, merely to show how irreconcilable they are with the chemical theory of food.

The experiments, which extend over a period of three years, embrace great varieties. The dog is kept without food for several days, and the waste of tissue calculated. The dog is fed on meat alone, freed, as far as possible, from fat; then he is fed on meat and fat, in varying quantities and proportions; then with meat and sugar; with meat and starch; with bread and starch; with bread alone; with meat and gelatine; with gelatine and fat; and with gelatine alone. The same dog is the subject of all these experiments, and his mode of life is rigorously uniform.

It is said by Liebig and his followers that fat is burned at once in the organism to supply the requisite animal heat, before it is converted into tissue; and the surplus which is not burned, is stored up among the tissues as so much accumulated material ready for burning when needed. One confirmation of this view is held to be the gradual loss of fat which takes place during the winter-sleep of hybernating animals, and the effect of starvation seen in the sudden leanness of the starved animal. Now, one of the constant results of the starvation-experiments of Bischoff and Voit is in direct contradiction to this hypothesis. They

state it as a law of the organism that the waste of tissue in a starving animal, for the supply of heat and motor-power, is always proportionate to the mass of the animal. "This relation of mass to waste is preserved also with respect to the separate parts of the animal, its flesh and its fat; and a certain interchangeableness is observed between the two. An animal rich in flesh wastes more flesh; an animal rich in fat wastes more fat." It thus appears that the amount of waste is not determined by the greater or less suitability of stored-up fat as a heat-producer, but is simply determined by the amount of fat which is exposed to the destructive oxygen. If the dog has a moderate amount of stored-up fuel with a large amount of good flesh, he does not, as the chemical theory would require, begin by burning all that fat before drawing upon his muscle; on the contrary, he spares much fat, and wastes much muscle. The truth seems to be, that both fat and muscle are subject to waste, to supply heat and motor-power; and not that the fat supplies all the heat, and the muscle all the power. This result is confirmed by the experiments of feeding the dog on flesh alone. When a certain amount of pure flesh, containing not more than one per cent of fat, was given, the dog not only developed the requisite heat, but developed more than when a large proportion of fat was given with a less amount of meat. In another direction this is confirmed; the dog fed on meat and fat, stored up the fat, and did not burn it, when the quantity of meat reached a certain amount.

Thus, from three several sides, Liebig's hypothesis is shown to be at fault; and neither the fat in the food, nor the fat stored up in the tissues, can be rightfully claimed as supplying the whole of the animal heat. That fat, when burned, will yield heat, no one ever thought of disputing. But the question at issue is, Does fat serve any other purpose in the organism besides that of fur

Ibid. 252.

nishing heat, and is it required simply as so much respiratory food? The untenableness of Liebig's view is fully shown when, to facts like those just named, we add his own confession, that nitrogenous substances also, when burned, yield heat. The only distinctions he pretends to rely on are two: First, that nitrogenous substances are never burned until after they have become plastic, and have served their plastic purposes, whereas fat is burned simply as combustible material, and never becomes plastic; this we have already seen to be entirely erroneous. Secondly, that although nitrogenous food will furnish animal heat, it is a much more expensive means of supplying heat than by a due admixture of fat. This may be true, or not true; at any rate it is an economic, not a physiological question.

It is right that I should add that Bischoff and Voit, in spite of the facts they themselves adduce, uphold Liebig's theory. But they do so on grounds which we have already seen to be untenable; they persist in affirming that fat and carbonaceous substances only serve the purpose of producing heat, and that although nitrogenous substances also, and inevitably, furnish heat, yet they do so at considerable expense. "Like everything else in the animal organism, this relation between nitrogenons and non-nitrogenous foods, as respects the demands of motor force

and heat, is most advantageously and simply constituted. If a large amount of nitrogenous substances is metamorphosed, and much force set free, then fat is spared and stored up, because in this metamorphosis the requisite amount of heat is also developed. If, on the contrary, no such amount of force is demanded, and a smaller amount of metamorphosis is necessary, then there is the fat ready to furnish the required heat, and save the tissues." Now, to answer this chemically plausible, but physiologically absurd, argument, it is enough to say that, were it true, violent exercise would make men fat, and idleness make them lean; because in violent exercise there would be such a consumption of tissue as to supply the requisite heat, without any call upon the fat. But really the arguments put forward are so weak, and so utterly oblivious of the real problem which has to be solved

namely, the nutrition of a very complex organism-that I am not disposed to trespass further on the reader's patience. It is enough to have shown that the facts collected by Bischoff and Voit furnish decisive arguments against the theory maintained by Liebig. In showing this, I have added one more justification of the criticism on the chemical theory which is made in The Physiology of Common Life.-Yours truly,

GEORGE HENRY LEWES.

A LEARNED judge, in passing judgment lately, declared that all lawyers must feel ashamed of the number of conflicting decisions bearing on the case before him. When a class of men devote their attention to a particular branch of physical or social science, they feel that it is not creditable for the public at large to see that there are wide differences of opinion among them as to the results of their study and experience. If two of the initiated lay down diametrically opposite opinions, one of them at least must be wrong, and the uninitiated murmur that some of these wise men are no better than their fellows, for the most ignorant individual generally knows sufficient to be able to give a wrong opinion upon any subject. In contemplating the recent legislation regarding India, and especially regarding the Indian army, we wonder how statesmen and soldiers can hold up their heads. The blue-books are one mass of contradictory opinions from men claiming to be high authorities on the subject. If a governor propounds one scheme as the panacea for those evils which affect our military system, a lieutenant-governor immediately decries it as certain to involve the empire in ruin. If a commander-in-chief devises a plan to organise the army, a military member of council at once steps forward to assure us that the disorganisation of the army will be effectually secured by its adoption. The public feels little enlightened by these discussions, and may reasonably doubt whether its rulers feel enlightened themselves. We are half afraid the Indian question is too intricate for the little wisdom with which the world is governed, and must hope that the measure of amalgamating the Indian and home services, which has been adopted amid doubts and difficulties, may, in spite of our forebodings, prove to be a step in the right direction after all. It would, we believe, be no difficult matter to fill many pages with curious extracts from the minutes of evidence recorded in the Blue-book

on this subject, but we shall merely give one from the claborate minute by Sir James Outram. Sir James is the great opponent of amalgamating the armies, and he is a man whose antecedents entitle him to be heard. He has shown himself a brave commander in the field, and his uncompromising honesty as a politician threw him temporarily under a cloud, from which he emerged only to shine more brightly than before. Yet in Sir James Outram's scheme for organising the army, the first physical qualification of which the cadet must bring a certificate, is that of being an expert swimmer-a useful accomplishment certainly, but which might surely be dispensed with in officers of any other cavalry_corps than the horse-marines. Sir James proposes that an officer who passes certain examinations for the adjutant-general's department shall be made a captain, after which, if he qualifies for the quartermaster-general's department, he becomes a major; and if he then pass an examination for the judge-advocate-general's department, he becomes a lieutenantcolonel-a pleasant arrangement for those who burn the midnight oil, but not for those who watch by the bivouac fires. We could add some equally curious extracts from the suggestions of Sir James's opponents, but they would serve nothing to our present purpose.

"Our only danger in India," said Lord Ellenborough, "is the native army;" and this being the case, we have no hesitation in saying that, while we hold India, our most important duty is to keep the native army obedient and contented. There may be other duties more pleasant and apparently more profitable, but those who neglect this one to help the spread of education, or improve the communications and resources of the country, have no claim to our approbation. If we only keep our army in order, but do nothing towards educating and civilising our fellow-subjects, we grossly neglect to fulfil the responsibilities of our situa