INFLUENCE OF EXTERXAL TEMPERATURE. 813 
show thai the effecl of tropical heat is to raise the mean temperature 
of the human body, but the im generally less than one degree. 
Crombie x found, as the result of 1288 observations upon himself, that 
the temperature of the mouth was about 0°23 higher in Bengal than the 
average in England, hut the difference was greater during the first few 
weeks of residence in the hot climate. 
On the other hand, some observers maintain that residence in a 
tropical climate does not raise the temperature of the body; thus 
Boileau 2 states that the normal axillary temperature is between 36°7 
and .".7 "2, Thornley 3 and Furnell 4 that it is invariably the same as in 
England, 36°9. 
^Numerous careful observations recently made by Xeuhauss 5 during a 
voyage round the world, show the effect of external heat upon the daily 
temperature, pulse, and discharge of urine. The following are some of the 
results : — 
Temperature 
of Air. 
Six A.M. 
Xoo.v. 
Ten p.m. 
Six p.m. 
Remarks. 
Temperate 
ZOXE. 
Min. Max. 
ll°-5 I3°-6 
36°-6 
55 
36 :, 9 
55 
36°-8 
56 
37°'l 
62 
Temperature iu"| ,, „ , , 
Mean of twenty 
rectum 5- ■, J 
Pulse J da ^ 
Tropical Zone. 
23'-9 26 6 
36° -9 
37 -Z 
37°-l 
37°-3 
Temperature inl ,, - x 
rectum - Mean of twenty- 
Pulse J five da y s - 
60 
6S 
64 
72 
The influence of the different seasons of the year — Xo marked 
effect upon the heat of the body can be ascribed to the different seasons 
of the year, apart from that due to variations in external temperature. 
The numerous observations made 1 ty Davy c upon himself tend to show 
that the temperature of the mouth is somewhat lower during the winter 
months in England, and slightly higher during the summer ; a similar 
series taken in the tropics, in Barbadoes, where the mean annual 
temperature of the air is 26°'7, and the range throughout the year is 
about 8°, shows no marked variation during the different seasons. 
Jousset" found that the cool season caused a fall of two- or three- 
tenths of a degree in the average temperature of natives of the tropics. 
From Bosanquet's 8 observations of the rectal temperature, it appears 
that the highest sustained average temperature occurred in the winter 
and early spring months. These determinations were made upon 
himself four times a day for a period of three years. 
A few observations have been made on the influence of winter and 
summer upon the temperature of animals. Thus Edwards 9 found in 
the case of sparrows that the mean temperature rose progressively from 
1 Indian Ann. Med. Sc., Calcutta, 1873, vol. xvi. p. 550. 
2 Lancet, London, 1878, vol. i. p. 413. 
3 Ibid., 1878, vol. i. p. 554. * Ibid., 1878, vol. ii. p. 110. 
5 Virchow's Archie, 1S93, Bd. exxxiv. S. 365. 
6 Phil. Trans., London. 1845, pt. 2, p. 319 ; and 1850, p. 437. 
7 Arch, de mid. nav., Paris, 1883, tome xl. p. 124. 
8 Lancet, London, 1895, vol. i. p. 672. 
9 "Animal Heat," in Todd's "Cyeloppedia,"' vol. ii. p. 659. 
