NER VO US CONTR OL OF TEMPERA TURE. 85 7 
mass, and thus the loss of heat due to vasomotor paralysis is less serious 
than in a small animal. Animals also differ in their method of 
regulation : some, as in the case of man, have a well-developed vaso- 
motor system for the cutaneous surface, which is so Blightly protected by 
natural covering: others, as in the case of dogs, have a thick fur, and 
regulate their temperature chiefly by variations in the production of 
heat and in the loss of heat from the respiratory tract. The distribu- 
tion and pari, played by the sweat glands varies greatly, as shown by a 
comparison of men and h< »rses with clogs and cats. It is to be noticed 
further, in this respect, that marked differences exist even in individuals 
of the same race and variety : thus, some men and horses sweat much 
more readily and profusely than others. 
In addition to the above factors, it is necessary to consider the 
external conditions under which the injured animal finds itself. The 
external temperature greatly modifies the part played by the loss of heat 
from the paralysed parts/ Most animals adopt a different posture, 
according to their need of heat or cold ; thus a heated dog, rabbit, or 
mouse lies with extended trunk and Limbs, whereas the same animal 
when it is cold, coils or huddles itself together. It is almost unneces- 
sary to point out that a paralysed animal could not assume these 
instinctive postures. A normal rabbit tied down in an extended position 
loses an abnormal quantity of heat, and its temperature falls, and in 
some cases the body is so greatly cooled that death results. 1 
The above facts must therefore be borne in mind during any ex- 
amination of the effects of section or injury of the spinal cord. 
Attention was first drawn to the influence of the nervous system upon 
temperature, by the experiments and clinical observations of Benjamin 
Brodie. 2 He found that, after the head of an animal was cut off, or the 
cord divided high up in the cervical region, the circulation of the blood 
still continued when artificial respiration was performed, but the tem- 
perature fell even more quickly than in a dead animal. This Brodie 
correctly attributed to the great loss of heat from the circulating blood, for 
if the circulation was stopped by ligature of the heart, the fall of tem- 
perature was much retarded. It was also found that woorara (curari) and 
essential oil of almonds, by suspending the action of the central nervous 
system, also caused a fall in temperature. Brodie further compared the 
discharge of carbon dioxide by normal rabbits with that of rabbits with 
the brain removed or poisoned by woorara or the essential oil of almonds : 
he states that the same quantity of carbon dioxide is formed in each of 
these cases, and therefore that the heat production is not clue to chemical 
change but to nervous action. This conclusion is not warranted by the 
results of the determinations of the respiratory exchange, and the 
results themselves are not comparable, for, even when it was possible, the 
experiments were not made upon the same animals. 
The work of Brodie led to numerous experiments and discussions on 
this subject by Chossat, 3 Hale, 4 Legallois, 6 Wilson Philip, 6 Hastings, 7 
1 Legallois, Ann. de chim. etphys., Paris, 1817, Se>. 2, tome iv. p. 21. 
2 Phil. Trans., London, 1811, vol. ci. p. 36 ; 1812, vol. cii. p. 378 ; Mcd.-C'hir. Trans., 
London, 1837. vol. xx. p. 146. 
3 Deutsches Arch. f. d. Physiol., Halle, 1822, Bd. vii. S. 282. 
4 London J/< </. arid Phys. Journ.. vol. xxii. 
5 Ann. de chim. etphys., Paris, 1817, Ser. 2, tome iv. 
6 '-'Experimental Inquiry into the Laws of the Vital Functions," London, 1818, 2nd 
edition, p. 197 et seq. 
7 Quart. Journ. Sc. Lit. and Arts, London, 1823, vol. xiv. p. 96. 
