8o 4 ANIMAL HEAT. 
temperature of the air. Newly-born guinea-pigs, however, were able 
to maintain their temperature, provided that the exposure to cold was 
not very great. Edwards therefore divided the young warm-blooded 
animals into two classes, the warm-blooded and the cold-blooded. In 
the former class the young animals are at birth blind, helpless, in some 
cases naked, and cannot maintain their temperature. The members of 
the latter class are even at birth in a condition of great development ; 
their eyes are open, they are active, and maintain a fairly constant 
temperature. It was also found that young birds could be classified 
in a similar manner. As the animal grows, the fall in temperature on 
exposure becomes less and less, and about the fifteenth day after birth 
a fairly constant temperature can be maintained. 
Edwards showed by comparative experiments that the fall in tem- 
perature on the exposure of newly-born animals was not due to the 
greater cutaneous surface, in proportion to the mass of the body, as com- 
pared with the ratio in adults. The absence or presence of feathers or 
fur was only of secondary import, for an adult sparrow was aide to 
maintain its temperature even after all its feathers had been plucked 
out. 
Eaudnitz 1 in 1888 discussed very fully the temperature of infants. 
He made observations upon the variations of temperature in infants at 
birth and during the first few days after birth. The influence of the 
large cutaneous surface in relation to the mass of the body, and the loss 
of heat from the skin, were shown by experiment to be only secondary 
causes of the irregular temperature. Observations made upon the effect 
of affusions of cold water showed that the rectal temperature in infants 
a day or two old rose in the case of strong subjects, but remained 
stationary or fell in the case of the weak. Eaudnitz concludes that 
the imperfect development of the power of regulating temperature is 
the chief cause of the variable temperature in infants : and it has been 
shown by the writer 2 that this is also the cause in the case of young 
immature animals. 
Before birth the temperature of the infant is slightly higher than 
that of the mother's uterus ; a at birth the average rectal temperature 
is 37°'5 (99° - 5). Soon after birth, especially after the first bath, the 
temperature falls to about 36 0, 75 (98°*15), and during the next week or 
two rises somewhat, and remains fairly constant between 37°"25 (99 o, 05) 
and 37°'6 (99°'68). These figures are to be looked upon only as average 
results, for all observers appear to agree that the daily fluctuations of 
temperature are greater and more uncertain in children than in adults. 4 
1 Ztschr.f. Biol., Mtinchen, 1888, BJ. xxiv. S. 423. At the end of this paper is a very 
complete list of papers bearing upon the subject. 
2 Pembrey, Journ. Physiol., Cambridge and London, 1895, vol. xviii. p. 36-3. 
3 Wurster, Berl. Jclin. Wchmckr., 1869, Nr. 37; Alexceff, Arch. f. Gynaek., Berlin, 
Bd. x. S. 141; Fehling, ibid., Bd. vii. S. 146; Preyer, " Specie'lle Physiologie des 
Embryo, 1 ' Leipzig, 1885, S. 362. 
4 Barensprung, Arch. f. Anat., Physiol, u. wisscnsch. Med., 1851, S. 138; Finlayson, 
"On the Normal Temperature of Children," Glasgow Med. Journ., 1869, p. 186 ; Squire, 
Trams. Obst. Soc. London, vol. x. p. 274 : Eaudnitz, Ztschr. f. Biol., Miinchen, 1888, 
Bd. xxiv. S. 423; here other references will be found; Jiirgensen, "Die Kbrperwarme 
des gesunden Menschen," 1873, S. 49 ; Davy, "Researches," London, 1S39, vol. i. p. 156 ; 
Crombie, Indian Ann. Med. Sc., Calcutta, 1873, vol. xvi. p. 594 ; Mignot, These de Paris, 
1851 ; Wurster, Berl. klin. Wchnschr., 1869, Bd. vi. S. 37 ; Andral, Compt. rend. Acad. 
d. sc, Paris, 1870, p. 815 ; Roger, Arch. gen. de mid., Paris, Ser. 4, tome v. p. 273 ; " De 
la temperature chez les enfants," Paris, 1844 ; Lepine, Gaz. mt'd. de Paris, 1870 ; Fehling, 
Arch./. Gynaek., Berlin, 1874, Bd. vi. S. 385. 
