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as far as portraiture goes, be unauthen- | calorimeter. Within the last few years tic, seeing that they were painted two Professor d'Arsonval of Paris adopted hundred years after her death ; run it the same principle, and I myself have to ground, in whatever direction mod- worked out the theory of it, and conern cynicism or dogmatic agnosticism structed apparatus, with which I have suggests, the beauty of the strong im- made a great number of experiments. pression Santa Fina can produce will The animal to be experimented upon ever remain the best result of the long in my apparatus is placed in a chamber excursion to San Gimigniano delle Belle surrounded by double metallic walls. Torri.

The heat given out by the animal raises the temperature of the air contained between the walls, until the radiation

from the outer surface causes a loss of From Nature.

heat equal to the amount gained by it ANIMAL HEAT AND PHYSIOLOGICAL

from the animal. This state of things CALORIMETRY.1

having been established, the temperaThe problem of animal lieat is one of ture of the air becomes constant, the the oldest problems of scientific specu- gain and loss of heat being equal. In lation. Nevertheless it is only within this way the heat given out can be calrecent years that we have been able to culated.2 speak of it in terms of modern knowl- The chamber containing the animal edge.

is well ventilated by aspiration. If we Among the earliest contributors to measure the volume of the air aspired such knowledge we may cite John and conduct a part of it through liquids Mayow and Joseph Black. Mayow was absorbing cabonic acid, the amount of the first to suggest that atmospheric air this gas given out by the animal can be is not a simple element and that its measured. In another series of exper" nitro-aeric particles,” in combining iments the amount of oxygen absorbed with the blood in the lungs, produce by the animal was also measured. The the animal heat, while Black demon- combination of apparatus I made use of strated that the air expired by the lungs for this purpose is a variation of the contains fixed air" or, as we now call method invented by Regnauit and Reiit, carbonic acid.

set. Priestley discovered oxygen gas in I shall not weary you with a long 1771, but Lavoisier was the first to enumeration of all my experiments. show that this constituent of the air is All I wish is to give a brief account of taken in by the blood in the lungs, and some of the results, which I think are that its combination with the carbon, of interest from a general biological which is a regular constituent of all point of view. organic matter, produces animal heat in In the first place, I may mention my the same way as in all combustions. experiments on fever. The high teniLavoisier was the first, too, who meas- perature in cases of febrile disease - is ured the heat produced by an animal, it the result of greater heat producmaking use of the ice calorimeter, con- tion ? Are we to assume that certain structed by himself and Laplace, while poisons taken into the body, or proCrawford nearly at the same time made duced in it by microbes, stimulate the investigations with an apparatus similar nervous system, or directly influence to our water calorimeter.

the tissues in such a way as to cause Neither form of apparatus is very greater oxidation, and thus to produce suitable for this purnose. Scharling, more heat ? Vogel, and Him made use of an air That is the opinion of many medical that neither the expiration of carbonic Most of my studies were conducted acid nor the excretion of oxidized ni- with a view to explain the connection trogenous matter is increased to such between heat production and other a degree as to account fully for the rise physiological functions, and the influof temperature. Therefore Traube, the ence of external circumstances on it. late clinician of Berlin, proposed the Higher animals, mammals and birds, theory that the rise of temperature in maintain their own temperature nearly fever is caused, not by greater heat pro- at the same degree, even when the duction, but by greater retention of heat. temperature of the surrounding air

men, but it met with the great difficulty 1 Paper by Professor Rosenthal of Erlanger, read before the Bioloripal Section at the Edinburgh 2 For a fuller account see my papers in Archiv meeting of the British Association for the Ad. fiir Physiologie, 1889, and in Sitzungsber. d. K. vancement of Science,

preuss. Akad. d. Wissensch. 1888-1892.

On producing fever in animals by in- changes within large limits. Is this jection of various putrid substances, I regulation, as we call it, caused by adapfound that at the beginning of the tation of heat procluction to the greater fever, heat production is not increased, or smaller loss, or are there means to that the loss of heat is diminished, and keep the loss constant in spite of the that the difference between the normal changing difference between the animal loss and that observed in the period of and surrounding objects ? rising temperature is sufficient to cause On measuring the heat production of the febrile rise. When the tempera- the same animal in cold and warm air, ture reaches its highest point the I found that it is smallest in air of meamount of heat given out rises and dium temperature, i.e., about 15° C., comes to its normal rate. Finally, becoming greater in lower and in higher when the fever begins to subside, dur- temperatures. Thus an animal proing the period of falling temperature, duces and loses nearly the same amount the loss of heat is greatly increased. of heat in air at 5° as in air at 25°. In

All this is in perfect accordance with this case regulation of the animal temTraube's theory. Nevertheless, I can- perature can be effected only by changes not say that heat production is never of the co-efficient of emission of heat augmented in fever. I have not yet from the skin, caused by changes of been able to make many experiments circulation. But for longer periods that on man. There are two great difficul- regulation is insufficient. In winter ties in the way, and the greatest is the time we use thicker clothing, we need impossibility of making a strict com- more food, and if the cold is very great, parison between the heat production in we produce more heat by muscular acfever and that in the normal state, ex- tion. In accordance with that expericept in cases of the regular intermittent ence, I found that animals produce type. Malaria, once so frequent in more heat in winter than in summer. several parts of Germany, nowadays, If nourished with the same food, suttithanks to hygienic improvements, is cient to maintain their weight constant very seldom met with. So I have been in winter, they do not oxidize the whole able to inake only two experiments on in summer, and therefore they gain in an individual afflicted with intermittent weight. It is remarkable that similar fever, some on invalids with abdominal changes were observed by Dr. Karl typhus (typhoid fever), some on cases Theodor, Duke of Bavaria, in the of pneumonia, and others in cases of amount of carbonic acid expired by a fever caused by the injection of Koch's cat, in the case of which he measured tuberculine during the short time when the expiration of this gas during five such injections were practised in the months. hospitals of Erlangen.

Many experiments have been made I found a small but real augmentation to find the combustion heat of our foodlof heat production, and therefore I am stuffs. For want of direct animal calinclined to suppose that the question is orimetry, physiologists used these data not yet solved. Perhaps there are two for calculating the heat produced by causes able to raise the temperature in living beings; but as my experiments fever, one of them prevailing in some show, there is frequently no exact accases or types of fever.

In these cases

cordance between the two.

Richly nourished animals produce body in the form of carbonie: acial an: less, sparely nourished ones more, heat nitrogenous matter like urea. What in than the calculation gives. Between a longer period is burnt in such a way, 'the two cases there is a third one in we can, with a certain degree of exactanimals sufficiently nourished, viz., such ness, make out by chemical examina· as take in so much nutriment as serves tion of the constituents of food on the to maintain their weight unchanged for one hand, and of the excretions on the a long time. · this case only the other. We can make up, in such a amount of heat produced is really equal way, a balance account for gain and to that calculated upon the combustion loss of the animal, like the balance acof the constituents of food. But also count of a merchant. But such an in this case variations are observed, account gives no exact knowledge, becaused by change of temperature, mus-cause we have no means of completing cular motion or other circumstances, so it by taking an inventory.

We are, as that only the middle figures correspond regards the living body, in the same exactly to the theoretical value. position as a political economist, who

Thus, if a well-nourished animal is kuows the amount of goods imported starved the heat production remains into and exported out of a country, but unchanged from three to four days, the does not know what has become of the animal burning its stored-up materials goods stored up or used up in the counand losing much of its weight ; only try itself. Therefore political econothen is it suddenly reduced to a lower mists do not now regard the mere amount. If now food is given again, balance of trade as being so important heat production remains small, the as they formerly thought. weight increases, and then, three or Physiology, like all branches of seifour days later, the heat production in- ence, begins with a mere description of creases and reaches its former amount. processes observed. With the progress

If a sufficiently nourished animal of our knowledge, reason tries to contakes in all its food once a day, the nect these processes one with another, heat production varies very regularly and with those going on in lifeless uain the twenty-four hours. Two hours ture. What we call understanding is after the meal it begins to rise, comes nothing else thau knowing such conto its maximum point between the tifth nections. Now in the case of bodily and seventh hour, falls suddenly be- income and expenditure, it is easy to tween the eleventh and twelfth hour. observe that all materials going out of In the second half of the period the the system are more oxidized than those changes are small, the minimum point taken in as food, and reason tells us being usually in the twenty-third hour. that the combination of these food ma

Similar changes go on in the expira-terials with the oxygen inspired must tion of carbonic acid. But after the be the source of animal heat. Hence', meal it rises much more rapidly, and we have no doubt that the amount of therefore comes earlier to its maximum heat produced must correspond to the point. Thus the ratio between heat amount of chemical processes going on production and expiration of carbonic during the same time. But these procacid is not a constant. This is true not esses we cannot observe directly ; we only in the daily period. The varia- can only observe the final products cartions are seen to be still greater when bonic acids and others, when they leave we compare different animals, or the the body. But by some of the proesame animal at different times and in esses heat may be produced or absorbech different states of nutrition.

without any visible change of the body By such researches we are enabled to as a whole, viz., by solution of solid examine more exactly what chemical matter, by splitting highly complex changes are going on in the animal sys- substances into more simple ones, by tem. The materials afforded by food forming sugar out of starch or glycogen are all oxidized at last, and leave the 'out of sugar. Considering this, we without any

need not wonder that for a long time it the eddy of the river, viz., that the was impossible to answer the question matter which flows into it has a differwhether there is any other source of ent chemical composition from the heat production in animals besides matter which flows out of it, but in oxidation. Only long continued calori- addition, matters which make up the metric measurements have enabled me eddy in a given time, change, if I may to fill up this gap." This doue, I so say, their chemical value, combine thought it possible to discover also with or separate from each other, something about these inner processes,

visible change of the by comparing, hour for hour, the heat whole system. production with the excretion of car- The study of heat production is of bonic acid, and with the absorption of the greatest value. No doubt, the oxygen.

study of the vital processes becomes If the ratio between the heat pro- more complicated when we take into duced and the carbonic acid expired account the invisible internal changes changes, this cannot be explained oth- occurring in the body. But simplicity erwise than by the fact that different is not the highest aim in scientitic inchemical substances are burned. Each quiries ; the highest possible exactness substance, according to its chemical is that to which we must aspire. Hapconstitution, gives out, when oxidized, pily, the history of science shows that a certain amount of carbonic acid, and after trying several ways to solve comproduces a certain amount of heat. plex problems, we find that one of But in the system it is a mixture of dif- them leads to a higher point of view, ferent substances which come to be whence things appear in all their comoxidized. This mixture changes, not pleteness, simplicity and distinctness. only in animals differently nourished, Towards such a point of view my rebut also in the same animal in different searches are but the first step. Let us periods of digestion. After a rich meal, hope that the united forces of many what comes into the circulation first physiologists will shorten the time necmust be that part of the food that is essary for the completion of the work. easily and rapidly digested and easily and rapidly absorbed. Such substances are the proteid matters. Later, the other constituents of the food, espe

From The Westminster Budget. cially fat, come to the tissues, where BALMORAL STORIES OF THE ROYAL

FAMILY. they are burned. Now fats, for the same amount of carbonic acid, produce PRINCESS ALICE's husband, the late far more heat than proteids ; so, during Grand Duke of Hesse, was much liked the first hours of digestion the afflux of at Balmoral. His frank and genial oxidizable matter to the tissues being manner won all hearts.

“ He was alvery great, both heat production and ways so nice !” A scarf-pin he gave to expiration of carbonic acid increase, one of the servants was shown me ; a but the latter in a far higher degree pretty jewelled bit, with over thirty than the former.

tiny pearls. He was generous to the The animal body may be compared, gillies, who by no means have an easy as Professor Huxley so well says, to an time during the fishing and deer-stalkeddy in a river, which may retain its ing seasons ; and he did not tell tales shape for an indefinite length of time, out of school. One day, when his party though no one particle of the water were returning from deer-stalking, they remains in it for more than a brief found that the coachman who had been period. But there is not only the dif- in waiting at the appointed place had ference between the animal eddy and improved his leisure by imbibing vast 1 See also my address delivered to the general unfit to ride – in fact, tumbled off his

quantities of whiskey, and was totally meeting of the German Association of Naturalists at Bremen, 1870.

horse as often as he was lifted on.

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Thereupon he was stowed into the cart has passed the least time here since his with the dead deer, and the Duke of boyhood. The Duke of Connaught is Hesse sprang upon the horse and served often here, and the Prince of Wales is as postilion. He conveyed the party looked upon as a son of the soil. I in safety to the stables, and as he role heard two cottagers talking over a story into the yard shouted out “ Take off !” concerning the three one day. It which is the signal for the hostlers sounded somewhat familiar to me. It given by the coachman. • Take off may be an old story; and it may be a yourself !” was the reply, and great was manufactured one. “ But," said the the consternation when it was found 10 old dame, who had known them from whom they had spoken so cavalierly: childhood, and evidently still viewed But, bless you ! the duke didn't mind them as a trio of extremely lively lads, it; and, what was still better, he did " it was just what they would have not betray the drunken coachman, who liked.” The three had been fishing was sure in his own mind — when he some distance from Balmoral, and were came to that miud — that the next day waiting at the appointed place for the would be that of his dismissal.

wagonette to take them home. A boy It has often been interesting to me to with an empty machine came along, observe the tone in which different mem- and, seeing them standing there, asked bers of the royal family are mentioned where they were going. - a tone indicative of their special char- " To Balmoral." acteristics. A lad of eighteen or there- “Would they ride with him ?" abouts, a lad with an

“Oh, yes ;” and they all got in. Scotch face, talked enthusiastically to “And what may you do at Balmome of the Princess Louise (Mar- ral ?” asked the boy of the Prince of chioness of Lorne). “She is so bright Wales, who sat beside him, the whole and jolly to talk with !” says he, and, three, it seems, being strangers to the on the whole, thinks he likes her best. lad. Others dwell on the goodness of the “I am the Prince of Wales." Princess Beatrice, who is to them a true Ау y? and who may that chap be ? " child of Deeside, so much of her life indicating with his thumb over his has been spent there. The tenantry shoulder the second son of her Majesty. gave her a handsome four-in-hand when “ He is the Duke of Edinburgh.”. she married, of which gift " she was 66 And t'other one ?” with another very proud,” they will tell you. At a jerk of his thumb. suggestion that some people called her “ The Duke of Connaught.” proud, an old cottager remonstrated. The boy wore an air of thought for " Na, na! her manner was different some moments, then he spoke again. from the rest; but she was brought up ** Perhaps you'd like to know who I different — was with older folk mostly. am ?” he said. The other children were taken by their The prince intimated that he would. governess or nurse to the cottages to “I am the Shah of Persia," said the give their own little gifts, and they lad, not to be outdone in this assumpplayed with the cottage children an tion of titles. hour every day. It was different with From internal evidence, I should the Princess Beatrice. But she wasna judye that this story originated at or proud. Na, na!"

about the time of the visit of the shah Of the sons, the Duke of Edinburgh of Persia and his suite to Balmoral.

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