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 ever remain the best result of the long excursion to San Gimigniano delle Belle Torri. From Nature. ANIMAL HEAT AND PHYSIOLOGICAL THE problem of animal heat is one of the oldest problems of scientific speculation. Nevertheless it is only within recent years that we have been able to speak of it in terms of modern knowledge. Among the earliest contributors to such knowledge we may cite John Mayow and Joseph Black. Mayow was the first to suggest that atmospheric air is not a simple element and that its nitro-aeric particles," in combining with the blood in the lungs, produce the animal heat, while Black demonstrated that the air expired by the lungs contains fixed air" or, as we now call it, carbonic acid. The animal to be experimented upon in my apparatus is placed in a chamber surrounded by double metallic walls. 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 heat equal to the amount gained by it from the animal. This state of things having been established, the temperature of the air becomes constant, the gain and loss of heat being equal. In this way the heat given out can be calculated.2 The chamber containing the animal is well ventilated by aspiration. If we measure the volume of the air aspired and conduct a part of it through liquids absorbing cabonic acid, the amount of this gas given out by the animal can be measured. In another series of experiments the amount of oxygen absorbed by the animal was also measured. The combination of apparatus I made use of for this purpose is a variation of the method invented by Regnault and Rei set. I shall not weary you with a long enumeration of all my experiments. All I wish is to give a brief account of some of the results, which I think are of interest from a general biological point of view. Priestley discovered oxygen gas in 1771, but Lavoisier was the first to show that this constituent of the air is taken in by the blood in the lungs, and that its combination with the carbon, which is a regular constituent of all 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 temLavoisier 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 greater oxidation, and thus to produce more heat ? Neither form of apparatus is very suitable for this purnose. Scharling, Vogel, and Hirn made use of an air 1 Paper by Professor Rosenthal of Erlanger, read before the Biological Section at the Edinburgh meeting of the British Association for the Advancement of Science, That is the opinion of many medical men, but it met with the great difficulty 2 For a fuller account see my papers in Archiv für Physiologie, 1889, and in Sitzungsber. d. K. preuss. Akad. d. Wissensch. 1888-1892. that neither the expiration of carbonic acid nor the excretion of oxidized nitrogenous matter is increased to such a degree as to account fully for the rise of temperature. Therefore Traube, the late clinician of Berlin, proposed the theory that the rise of temperature in fever is caused, not by greater heat production, but by greater retention of heat. On producing fever in animals by injection of various putrid substances, I found that at the beginning of the fever, heat production is not increased, that the loss of heat is diminished, and that the difference between the normal loss and that observed in the period of rising temperature is sufficient to cause the febrile rise. When the temperature reaches its highest point the amount of heat given out rises and comes to its normal rate. Finally, when the fever begins to subside, during the period of falling temperature, the loss of heat is greatly increased. Most of my studies were conducted with a view to explain the connection between heat production and other physiological functions, and the influence of external circumstances on it. Higher animals, mammals and birds, maintain their own temperature nearly at the same degree, even when the temperature of the surrounding air changes within large limits. Is this regulation, as we call it, caused by adaptation of heat production to the greater or smaller loss, or are there means to keep the loss constant in spite of the changing difference between the animal and surrounding objects? On measuring the heat production of the same animal in cold and warm air, I found that it is smallest in air of medium temperature, i.e., about 15° C., becoming greater in lower and in higher temperatures. Thus an animal produces and loses nearly the same amount 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, suffithanks 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 make only two experiments ou 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. In these cases I found a small but real augmentation to find the combustion heat of our foodof 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. Many experiments have been made cordance between the two. Richly nourished animals produce | body in the form of carbonie acid and 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 animals sufficiently nourished, viz., such as take in so much nutriment as serves to maintain their weight unchanged for a long time. In this case only the amount of heat produced is really equal to that calculated upon the combustion of the constituents of food. But also in this case variations are observed, caused by change of temperature, muscular motion or other circumstances, so that only the middle figures correspond exactly to the theoretical value. we can, with a certain degree of exactness, make out by chemical examination of the constituents of food on the one hand, and of the excretions on the other. We can make up, in such a way, a balance account for gain and loss of the animal, like the balance account of a merchant. But such an account gives no exact knowledge, because we have no means of completing it by taking an inventory. We are, as regards the living body, in the same position as a political economist, who Thus, if a well-nourished animal is knows 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; ouly 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 scifour 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 takes in all its food once a day, the heat production varies very regularly in the twenty-four hours. Two hours after the meal it begins to rise, comes to its maximum point between the fifth and seventh hour, falls suddenly be-income and expenditure, it is easy to tween the eleventh and twelfth hour. In the second half of the period the changes are small, the minimum point being usually in the twenty-third hour. Similar changes go on in the expiration of carbonic acid. But after the meal it rises much more rapidly, and therefore comes earlier to its maximum point. Thus the ratio between heat production and expiration of carbonic acid is not a constant. This is true not only in the daily period. The variations are seen to be still greater when we compare different animals, or the same animal at different times and in different states of nutrition. By such researches we are enabled to examine more exactly what chemical changes are going on in the animal system. The materials afforded by food are all oxidized at last, and leave the of our knowledge, reason tries to connect these processes one with another, and with those going on in lifeless nature. What we call understanding is nothing else than knowing such connections. Now in the case of bodily observe that all materials going out of the system are more oxidized than those taken in as food, and reason tells us that the combination of these food materials with the oxygen inspired must be the source of animal heat. Hence, we have no doubt that the amount of heat produced must correspond to the amount of chemical processes going on during the same time. But these processes we cannot observe directly; we can only observe the final products carbonic acids and others, when they leave the body. But by some of the proc esses heat may be produced or absorbed without any visible change of the body as a whole, viz., by solution of solid matter, by splitting highly complex substances into more simple ones, by forming sugar out of starch or glycogen out of sugar. Considering this, we 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 done, I so say, their chemical value, combine thought it possible to discover also with or separate from each other, something about these inner processes, without any visible change of the by comparing, hour for hour, the heat whole system. production with the excretion of carbonic acid, and with the absorption of oxygen. The study of heat production is of the greatest value. No doubt, the 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 scientific 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, especially fat, come to the tissues, where they are burned. Now fats, for the same amount of carbonic acid, produce far more heat than proteids; so, during the first hours of digestion the afflux of oxidizable matter to the tissues being very great, both heat production and expiration of carbonic acid increase, but the latter in a far higher degree than the former. From The Westminster Budget. BALMORAL STORIES OF THE ROYAL FAMILY. "He was al PRINCESS ALICE'S husband, the late Grand Duke of Hesse, was much liked at Balmoral. His frank and genial manner won all hearts. ways so nice!" A scarf-pin he gave to one of the servants was shown me; a pretty jewelled bit, with over thirty tiny pearls. He was generous to the gillies, who by no means have an easy time during the fishing and deer-stalking seasons; and he did not tell tales out of school. One day, when his party were returning from deer-stalking, they found that the coachman who had been in waiting at the appointed place had improved his leisure by imbibing vast 1 See also my address delivered to the general quantities of whiskey, and was totally meeting of the German Association of Naturalists unfit to ride in fact, tumbled off his horse as often as he was lifted on. The animal body may be compared, as Professor Huxley so well says, to an eddy in a river, which may retain its shape for an indefinite length of time, though no one particle of the water remains in it for more than a brief period. But there is not only the difference between the animal eddy and at Bremen, 1830. 66 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 in safety to the stables, and as he rode into the yard shouted out "Take off!" which is the signal for the hostlers given by the coachman. "Take off yourself!" was the reply, and great was the consternation when it was found to whom they had spoken so cavalierly. But, bless you! the duke didn't mind it; and, what was still better, he did not betray the drunken coachman, who was sure in his own mind when he came to that mind that the next day would be that of his dismissal. It has often been interesting to me to observe the tone in which different members of the royal family are mentioned looked upon as a son of the soil. I heard two cottagers talking over a story concerning the three one day. It sounded somewhat familiar to me. It may be an old story; and it may be a manufactured one. But," said the old dame, who had known them from childhood, and evidently still viewed them as a trio of extremely lively lads, "it was just what they would have liked." The three had been fishing some distance from Balmoral, and were waiting at the appointed place for the wagonette to take them home. A boy with an empty machine came along, and, seeing them standing there, asked where they were going. "To Balmoral." "Would they ride with him?" Wales, who sat beside him, the whole "I am the Prince of Wales." - a tone indicative of their special characteristics. A lad of eighteen or thereabouts, a lad with an open sonsie Scotch face, talked enthusiastically to me of the Princess Louise (Mar-ral?" asked the boy of the Prince of chioness of Lorne). "She is so bright and jolly to talk with!" says he, and, on the whole, thinks he likes her best. Others dwell on the goodness of the Princess Beatrice, who is to them a true child of Deeside, so much of her life has been spent there. The tenantry gave her a handsome four-in-hand when she married, of which gift "she was very proud," they will tell you. At a suggestion that some people called her proud, an old cottager remonstrated. 66 Na, na! her manner was different from the rest; but she was brought up different was with older folk mostly. The other children were taken by their governess or nurse to the cottages to give their own little gifts, and they played with the cottage children an hour every day. It was different with the Princess Beatrice. But she wasna proud. Na, na ! " "Ay? and who may that chap be?" indicating with his thumb over his shoulder the second son of her Majesty. "He is the Duke of Edinburgh." "And t'other one?" with another jerk of his thumb. "The Duke of Connaught." The boy wore an air of thought for some moments, then he spoke again. "Perhaps you'd like to know who I am?" he said. The prince intimated that he would. "I am the Shah of Persia," said the lad, not to be outdone in this assumption of titles. From internal evidence, I should judge that this story originated at or about the time of the visit of the shah Of the sons, the Duke of Edinburgh of Persia and his suite to Balmoral. |