426 RESEARCHES UPON FEVER. 



in rabbits, upon successive non-fever days, and successive pyfemic febrile 

 days. These experiments were made, and in each case, the same irritation 

 being employed, the fall of temperature was much less upon the febrile 

 than upon the non-febrile days. This, of course, indicates that in fever 

 the inhibitory heat center is less powerful or active than in health. 



In conclusion, the results reached in the research may be summed up 

 as follows : 



First. Fever is a morbid nutritive process, whose characteristic is ex- 

 cessive heat production. 



Second. Heat evolution is under the control of the vasomotor nerve 

 centers (the dominating center being situated in the floor of the fourth 

 ventricle, near the point of the calamus) ; including also in man the 

 nerves which preside over the secretion of sweat. 



Third. Heat production is dominated by some higher nerve centers of 

 uncertain nature. 



Fourth. That in health there is in man, and probably in every animal, 

 a fixed temperature mean, and a normal diurnal variation of tempera- 

 ture having a regular rhythm, which is beyond the control of all dis- 

 turbing causes that do not force the organism beyond the limits^ of health. 



Fifth. That the maintenance of the normal variation is the result of 

 the play between the nervous systems which control the functions of 

 heat production and evolution. 



Sixth. Fever is a morbid process in which there is not only an eleva- 

 tion of the bodily temperature but also an increase in the chemical move- 

 ments of the stored materials, i. e., the tissues of the body; this increase 

 being usually but not always much more than sufficient to compensate 

 for the loss of food heat. The rise of the bodily temperature in fever is 

 not solely dependent upon increased heat production. 



Seventh. In fever there is usually a daily temperature variation par- 

 allel to and diftering from the normal health variation only in having a 

 higher mean. 



Eighth. That vasomotor paralysis in fever is followed by an almost in- 

 stantaneous sinking of temperature below normal, the fall bein g much more 

 rapid and excessive than is produced by vasomotor paralysis in health. 



Ninth. The higher centers which preside over the heat function are 

 not paralyzed in pyaemic fever in the rabbit, but are certainly less capa- 

 ble than in health of responding promptly and powerfully to stimula- 

 tion ; or in other words they are in a condition of paresis. 



Tenth. That the clinical phenomena of malarial and other fevers 

 indicate that the febrile motion is of nervous origin. 



Eleventh. That in most and probably in all continued fevers the symp- 

 toms are due to a poison in the blood. 



Twelfth. That fever appears to be caused by a loss of functional ac- 

 tivity in the higher centers which regulate the production and evolution 

 of animal heat due to the action of a blood poison upon the centers. 



Univeesity of Pennsylvania, 



Fhiladelphia, February 6, 1879. 



