ANIMAL HEAT 519 



of bacteriology, to support the idea that the rise of temperature 

 is of the nature of a protective mechanism, that fever is, indeed, 

 a consuming fire, but afire that wastes the body, to destroy the 

 bacteria. The streptococcus of erysipelas, for example, does 

 not develop at 39 to 40 C., and is killed at 39*5 to 41 C. 

 Anthrax bacilli, kept at 42 to 43 C. for some time, are attenu- 

 ated,' and when injected into animals confer immunity to 

 the disease. Heated for several days to 41 to 42 C., 

 pneumococci render rabbits immune to pneumonia. These 

 bacteriological results are supported to a certain extent by 

 clinical experience. For it has been observed that a cholera 

 patient with distinct fever has a better chance of recovery 

 than a case which shows no fever. But too much weight 

 ought not to be given to isolated facts of this sort, and 

 adverse evidence can be produced both from the laboratory 

 and the hospital. For although hens are immune to anthrax 

 under ordinary conditions, but can be infected by inocula- 

 tion when artificially cooled, frogs, equally immune at the 

 temperature of the air, become susceptible when artificially 

 heated. And it is impossible to deny that the use of 

 cold baths in typhoid fever is sometimes of remarkable 

 benefit. 



Distribution of Heat. The great foci of heat-formation the 

 muscles and glands would, if heat were not constantly leaving 

 them, in a short time become much warmer than the rest of the 

 body ; while structures like the bones, skin, and adipose tissue, in 

 which chemical change and heat-production are slow, would soon 

 cool down to a temperature not much exceeding that of the air. 

 The circulation of the blood ensures that heat produced in any 

 organ shall be carried away and speedily distributed over the whole 

 body ; while direct conduction also plays a considerable part in 

 maintaining an approximately uniform temperature. The uniformity, 

 however, is only approximate. The temperature of the liver is 

 several degrees higher than that of the skin, and the temperature of 

 the brain several degrees higher than that of the cornea. The blood 

 of the superficial veins is colder than that of the corresponding 

 arteries. The crural vein, for example, carries colder blood than the 

 crural artery, and the external jugular than the carotid. The heat 

 produced in the deeper parts of the regions which they drain is 

 more than counterbalanced by the heat lost in the more superficial 

 parts. When loss of heat from the surface is sufficiently diminished 

 by an artificial covering, or prevented by the protected situation of 



