ANIMAL HEAT 



607 



fall of temperature at night, a minimum in the early morning 

 and a morning rise. 



As to the relation of age and sex to temperature, it is only 

 necessary to remark that the mean temperature both of the 

 young child and of the old man is somewhat higher than that 

 of the vigorous adult ; but a point of more importance is the 

 relative imperfection of the heat-regulation in infancy and 

 age, and the greater effect of accidental circumstances on the 

 mean temperature. Thus, old people and young children are 

 specially liable to chills, 

 and a fit of crying may 

 be sufficient to send up 

 the temperature of a 

 baby. In infants an 

 hour or two old the 

 temperature may be as 

 low as 34 C. (93-2 F.) 

 or 33-0 C. (91-4 F.) 

 even when they are fully 

 clothed in a room at 

 15 C. (59 F.). It rises 

 gradually during the first 

 day or two, but shows 

 marked variations. On 

 the fifth day after birth, 

 e.g., the rectal tem- 

 perature ranged from 

 36-2 C. (97-16 F.) to 

 33*5 C. (92-3 F.) in a 

 child weighing 5j pounds 

 (Babak). The tempera- 

 ture of women is gene- 

 rally a little higher than 

 that of men, and is also 

 somewhat more variable. 



After death the body cools at first rapidly, then more slowly 

 (Fig. 201). But occasionally a post-mortem rise of temperature 

 may take place. In certain acute diseases (like tetanus) associ- 

 ated with excessive muscular contraction this has been especially 

 noticed ; in bodies wasted by prolonged illness it does not occur. 

 Nearly an hour after death, in a case of tetanus, the temperature 

 was found to be 45- 3, while before death it was 44^7 (Wunder- 

 lich). In dogs a slight post-mortem rise may be demonstrated, 

 especially when the body is wrapped up ; but when an animal 

 has been long under the influence of anaesthetics no indication 

 whatever of the phenomenon may be obtained. The explana- 

 tion of post-mortem rise of temperature is to be found : (i) In 



FIG. 201. CURVE OF COOLING AFTER DEATH : 

 GUINEA-PIG. 



Time marked along horizontal, and tempera- 

 ture along vertical axis. At a ether and 

 chloroform given to kill animal ; death, as 

 indicated by stoppage of the heart, took place 

 at b. The dotted line shows the course the 

 curve would have taken if death had occurred 

 at the moment the anaesthetics were given. Air 

 of room i7'6. 



