FEVER 



75 



creases the metabolism more than high fever, only causes in a 

 healthy man a rise of about i C. in the rectal temperature. When 

 the work is over, the temperature comes rapidly back to normal. 

 The essence of the change in fever is a derangement of the mechanism 

 by which in the healthy body excess or defect of average metab- 

 olism, or of average heat- 

 loss, is at once compensated 

 and the equilibrium of tem- 

 perature maintained. 



This derangement only lasts 

 as long as the temperature 

 is rising. -When it becomes 

 stationary at its maximum 

 we have again adjustment, 

 again equality of production 

 and escape of heat; but the 

 adjustment is now pitched 

 for a higher scale of tempera- 

 ture. A rough analogy, so 

 far as one part of the process 

 is concerned, may be found 

 in the behaviour of the 

 ordinary gas-regulator of a 

 water-bath. It can be ' set ' 

 for any temperature. That 

 temperature, once reached, 

 remains constant within nar- 

 row limits of oscillation; but 

 the regulator can be equally 

 well adjusted for a higher or 

 a lower temperature. It is, 

 however, important to note that the equilibrium is more unstable 

 in fever than in health, so that changes of external temperature more 

 easily depress or increase the temperature of a fever patient than of 

 a healthy man. 



Rosenthal has concluded from calorimetric observations that, in 

 the first stage of fever, while the temperature is rising, there is 

 always increased retention of heat. Maragliano actually found 

 evidence, by means of the plethysmograph, that the cutaneous 

 vessels are at this stage constricted, and that the constriction may 

 even precede the rise of temperature. The blood- flow in the feet 

 in cases of typhoid fever investigated by the calorimetric method 

 (p. 122) was not found to exceed the normal flow, and was usually 

 decidedly below the normal. Hyperexcitability of the vaso-con- 

 strictor mechanism of the peripheral parts, especially of the skin, 



45 



Fig. 226. Diagram to show tha Possible 

 Relations between Heat- Production and 

 Heat -Loss in Fever. 



