EVOLUTION OF HEAT. 545 



whole, there seems to be no strong reason for admitting the existence of an 

 inhibitory centre for the production of heat in the spinal cord, which is par- 

 alyzed on division of the cord, and for which some authors have contended. 

 In M. Tscheschichin's experiments, section of the pneumogastrics was not 

 observed to produce any remarkable effect upon the development or distribu- 

 tion of the animal heat in rabbits at least not until those pathological 

 conditions which have been already described ( 305), as resulting from 

 their section, had become established. Various pathological phenomena in- 

 dicate that the withdrawal of nervous influence from any part of the body 

 usually tends to produce a depression of its temperature, and this especially 

 in t!i o^vcvviities ; thin M:\ II. Earle 1 found the temperature of paralyzed 

 limbs slightly lower than that of sound limbs ; so Prof. Dunglison has no- 

 ticed that in one case of herniplegia of five months' standing, the temperature 

 of the axilla was 062 on the sound side, and 96 on the paralyzed; whilst 

 that of the hand was 87 on the sound side, and only 79-} on the paralyzed; 

 and in another case of only a fortnight's duration, the temperature of the 

 axilla was 100 3 on the sound side, and only 98? on the paralyzed, whilst 

 that of the hand was 94 on the sound side, and 90 on the paralyzed. 2 

 According to Folet, 3 the temperature of the paralyzed side soon after an 

 attack of hemiplegia is 1.8 Fahr. above that of the opposite side ; but, when 

 atrophy supervenes, the temperature falls again. The elevation is quite in- 

 dependent of the seat of the lesion of the nervous system. 



437. Local Variations. The blood is the means by which the uniformity 

 of the temperature of the body generally is maintained, and its mass enables 

 it to equalize the variable amounts that are produced in the several glands 

 and muscles it traverses, according to whether they are in an active or in a 

 quiescent condition. Warmed during its passage through the abdominal 

 and thoracic viscera, which are in constant functional activity, and which are 

 prevented from cooling by the thick layer of fat that covers the abdominal 

 parietes, the blood carries a high temperature to the extremities, where it 

 becomes gradually reduced, owing to radiation and conduction. If the heat 

 be prevented from escaping from the surface of the body by radiation or 

 evaporation, as in cases where the large size of the animal causes the capil- 

 laries of the skin to bear a comparatively small proportion to those of the 

 body generally, or when the animal possesses a thick coating of wool or fat, 

 or is kept in a warm atmosphere, 4 the temperature rises to a high degree: 

 when the opposite conditions are present, the temperature falls. The great 

 importance of the supply of blood to any part in maintaining its tempera- 

 ture is well shown by the experiments of M. Claude Bernard, from which 

 it appears that an elevation of temperature constantly takes place on one 

 side of the face, when the trunk which unites the Sympathetic ganglia of the 

 neck on that side is cut through ; this increase being not only perceptible to 

 the touch, but showing itself by a thermometer introduced into the nostrils 

 or ears, even to the extent of from 7 to 11 Fahr. When the superior cer- 

 vical ganglion is removed, the same effect is produced, and with yet greater 

 intensity. This difference is maintained for many months, and is not ap- 

 parently connected with the occurrence of inflammation, congestion, oedema, 

 or any other pathological change in the tissues, though the sensibility of 

 the parts thus affected is no less augmented than their temperature; more- 

 over, it is not prevented from manifesting itself by the division of any of the 

 cerebro-spinal nerves of the face. This exaltation of temperature, there can 



1 Mcd.-Chir. Trans., vol. vii. 2 Human Physiology, 7th edit., vol. ii, p. 238. 



3 G-siz. Hebdomad., 18G7, Nos. 12-14. 



4 See Naunyn and Quincke, Eeichert's Archiv, 18G9, pp. 174 and 521. 

 6 Gazette Medicale, Fevr. 21, 1852. 



