660 



ANIMAL HEAT. 



hands, and a degree and a half in the feet. This 

 temperature of the air may be regarded as a 

 mean, or intermediate between heat and cold, 

 and may be termed temperate (61 to 62 F.). 

 It was superior to that of the water by a degree 

 R., and yet the water of the bath, after immersion 

 in it for no longer a time than twenty minutes, 

 had reduced the temperature of the body 

 according to its parts from half a degree to a 

 degree and a half R. 



Effects of external temperature upon an 

 isolated part of the body. Under this head 

 let us examine, 1st, the extent of the effect, and 

 2nd, its influence on other parts. The facts 

 we shall borrow from the researches just 

 quoted, those namely of myself and M. 

 Gentil. The hand, at 29 R. (98 F.) having 

 been kept immersed in a tub of water cooled 

 down to + 4 R. (41F.), in all during twenty 

 minutes, five minutes after it had been taken 

 out of the water, marked no higher a tempera- 

 ture than 10 R. (55 F.) This experiment 

 shows how rapid and extensive, and how much 

 beyond what could have been anticipated, may 

 be the refrigerating effects of cold water applied 

 to an extremity. Another not less remarkable 

 result is the singular slowness with which the 

 temperature of an extremity is regained, 

 although exposed to the gentle warmth of the 

 air. The hand in the above experiment, after 

 the lapse of twenty-five minutes from the time 

 it was removed from the water, was still no 

 higher than 16* R. (69 F.), and after the 

 expiration of an hour and a half it was only 

 24 R. (87 F.). The foot, in the same cir- 

 cumstance?, gave nearly analogous results. 



In a number of experiments of the same 

 nature as the last, where one hand was plunged 

 in water cooled down by ice, the other hand, 

 which was not subjected to the actionof the cold 

 bath, lost nearly 5 R. in temperature. 



It is therefore apparent, 1st, that partial 

 chills, or the exposure of individual parts to 

 low temperatures, may be and are felt very 

 extensively even when the cold is not very 

 severe ; 2nd, that the chilling of a single part, 

 such as the hand or the foot, may cause a loss of 

 temperature in all the other parts of the body, 

 even far beyond what could have been pre- 

 sumed as likely or possible. These facts give 

 a key to the right understanding of the immense 

 influence which partial chills are capable of 

 exercising on the state of the general health 



Of the effects of partial heating. The hand 

 being immersed in water heated to the tem- 

 perature of 34 R. (109 F.),rose one degree of 

 the same scale, and the temperature of other 

 remote parts not immediately exposed to the 

 influence of heat were found to have risen in a 

 corresponding degree. Whence follows this 

 axiom, that we cannot either raise or lower 

 the temperature of any one part of the body 

 without all the other parts of the frame being 

 affected, and suffering a corresponding rise or 

 Jail in temperature, more or less according 

 to circumstances. We may further presume 

 from the comparison of these facts, that the 

 body and its parts are liable to variations of 

 temperature towards either extremity of the 



scale from the mean, much more considerable 

 than are generally imagined. This latter fact 

 will appear very evidently from the other 

 inquiries which are now to engage our atten- 

 tion. 



Effects of an excessively high or excessively 

 low external temperature upon the temperature 

 of the body. Hitherto we have only considered 

 the changes in the temperature of the body pro- 

 duced by moderate degrees of external heat and 

 cold. We now pass on to the examination of 

 the effects caused by extreme external tempera- 

 tures, and first of those that follow from 

 excessive heat; designating by excessive heat 

 any temperature that surpasses that of the 

 human body. On a summer's day, the 

 temperature of the air being 37, 77 c. 

 (100 F.), Franklin observed that the tempera- 

 ture of his own body was nearly 35, 55 c. 

 (96 F.). This fact, which is perhaps the first 

 of the kind noted, is highly deserving of atten- 

 tion. It proves that man, and by analogy 

 other animals, have a power of keeping their tem- 

 perature inferior to that of the air. As in the ob- 

 servation quoted there is no means of knowing 

 what effect the excessive external temperature 

 had produced upon the temperature of the 

 observer, recourse must be had to other facts. 

 In numerous experiments made in England by 

 Dr. Fordyce and his friends, and subsequently 

 by Dr. Dobson, in which these experimenters 

 exposed themselves to very high temperatures, 

 which on some occasions exceeded that of 

 boiling water, the heat of the body was never 

 observed to rise more than one, two, three, or 

 four degrees of Fahrenheit's scale at the utmost. 

 As in these experiments the object especially 

 proposed was to determine the degree of 

 external temperature which the body could 

 bear, all the attention which would have been 

 desirable was not given to determine the tem- 

 perature of the "body before, during, and 

 after the experiments. This is an omission 

 which is common to the experiments of For- 

 dyce and Dobson. The highest temperature of 

 the body noted by Dr. Dobson is 102 F., but 

 he does not mention the heat before the experi- 

 ment, nor does he notice the rate of cooling 

 subsequent to its termination. The highest 

 temperatures of the human body exposed to 

 excessive heats ever observed, were remarked 

 by Messrs. Delaroche and Berger in their own 

 persons. The temperature of M. Delaroche 

 being 56 56 c. (98 F.) increased 5 of the 

 centigrade scale, by remaining exposed in a 

 chamber the temperature of which was 80 c. 

 (176 F.). M. Berger, whose temperature was 

 the same as that of M. Delaroche, gained 

 4 c. by remaining for sixteen minutes in the 

 hot chamber at 87 c. (188, 5 F.). These 

 experiments are liable to this objection, that 

 the temperature was taken in the mouth in an 

 atmosphere of much higher temperature, which 

 might have some influence in raising the ther- 

 mometer. To arrive at conclusions against 

 which no kind of objection could be raised, 

 Messrs. Delaroche and Berger exposed them- 

 selves in succession in a box, out of which they 

 could pass their head ; the hot air or vapour of 



