Fever. 171 



which int;ro(hace inrogenctic substances into tlie body or occasion 

 their production in the system {infusion fever, deprivation fever). 

 The question has been asked whether fever is useful or harm- 

 ful to the body and whether it may not possibly have the definite 

 purpose of rendering infectious and toxic matters harmless. From 

 the fact shown b\- various experiments that temperatures from 40 to 

 42" C. may inhibit the growth of a number of bacteria, attenuate 

 their virulence or actually destroy them it has been conjectured 

 that the same effect is produced in the body by febrile h\perther- 

 mia, that the fever, "purifying by tire" as it were, is in reality a 

 factor in causing recovery. There are a number of experiments 

 which seem to uphold this idea : small experiment animals have 

 been showm to bear better (that is do not die as soon from) diph- 

 theria, chicken cholera and other infections if kept in an incubator 

 at 41 to 42° C. than when left in a lower atmosphere. The resistance, 

 however, does not depend upon the direct action of the higher tem- 

 perature on the microorganisms, as Wassermann has pointed out, 

 but upon the fact that the bod\- when kept warm is better able to 

 permit the action of its natural protective mechanism (phagocyt- 

 osis, antitoxine production). There is no evidence of any pur- 

 pose for the increased temperature: this is only 4 symptom and 

 a result of the exaggerated metabolism, and the favorable outcome 

 is brought about b\ the reactive production of antibodies. In a 

 similar manner the complications and sequels of a fever are not 

 to be imputed to the elevated temperature. C3f course, it does 

 cause increased rapidity of cardiac action and of respiration, loss 

 of appetite and perhaps parenchymatous changes : but the real point 

 of the fever is in the severity of the infection, in the toxic action of 

 the infectious microorganisms which contribute the real danger, and 

 the elevation of temperature is only the index of the latter. The 

 restilt of measures having for their purpose the reduction of tem- 

 perature (cold water treatment and antipyretics) is not in conflict 

 with this conception of the relative inutility of the tem- 

 perature in fever ; such m^easures manifest their beneficial influence 

 not only by reducing the temperature but also by inhibiting the 

 causes and by diminishing metabolism. 



Stages of Fever. The febrile course is usually separable into a 

 number of periods or stages. The inception of the fever, its initial 

 period (pyrogenetic stage, stadium incrementi^ chill stage) mani- 

 fests itself by general symptoms of fatigue, weakness, rough.ening 

 of the hairy coat, loss of appetite and rise of the internal tempera- 



