5i8 A MANUAL OF PHYSIOLOGY 



famous ' retention ' theory of Traube. At the height of 

 the fever there is often, though apparently not always, an 

 increase in the heat-production. After the crisis, while the 

 fever is subsiding, the rate at which heat is being lost rises 

 sharply. As to the explanation of the increase of metabolism 

 in fever, various views have been held. Some have gone so 

 far as to say that the increase is merely the consequence, 

 not the cause, of the rise of temperature. But the rebutting 

 evidence which has been brought against this view is strong 

 and, indeed, overwhelming. The increase of urea, for 

 example, is often much greater in fever than any increase 

 which can be brought about by artificially raising the tem- 

 perature of a healthy individual by means of hot baths. 

 Further, this excessive excretion of urea does not run parallel 

 with the rise of temperature in fever, but is generally most 

 marked after the crisis. During the stage of defervescence an 

 enormous amount of urea is sometimes given off. In a case 

 of typhus, in the mixed urine of the third and fourth days 

 after the crisis, no less than 160 grammes urea was found 

 (Naunyn), or nearly three times the normal amount for a 

 man on full diet. Again, when fever is caused by the in- 

 jection of bacteria or their products, the increase in the 

 carbon dioxide eliminated and oxygen consumed occurs even 

 when the temperature is prevented from rising by cold baths. 

 It seems perfectly clear, then, that the increase of metabolism 

 is, in many cases at least, a primary phenomenon of fever, 

 and it remains to ask whether the rise of temperature is 

 anything more than a superficial, and, so to speak, an 

 accidental, circumstance. The orthodox view for many 

 ages has undoubtedly been that the increase of temperature 

 is in itself a serious part of the pathological process, a 

 symptom to be fought with, and, if possible, removed. And, 

 indeed, it is not denied by anyone that the excessive rise of 

 temperature seen in some cases of febrile disease (to 43 C., 

 or even to 45), is, apart from all other changes, a most im- 

 minent danger to life, unless, as is sometimes the case (in 

 influenza, e.g., where a temperature of 44 has been observed), 

 the high temperature lasts only a short time. But some evi- 

 dence has of late been brought forward, mostly from the field 



