HEAT AND LIFE. 145 



origin, since the nerves, as we have seen, are the regulators 

 of thermic action. 



The use of the thermometer is the only exact method 

 of measuring the temperature in disease. Swammerdam, 

 in the middle of the seventeenth century, seems to have 

 been the first to have the idea of it. De Haen and Hunter, 

 in the last century, used it in their medical practice, but 

 its employment at the sick-bed has really only come into 

 importance in our day, thanks to the labors of Bouilland, 

 Gavarret, Roger, Hirtz, and Charcot, in France; Baren- 

 sprung, Traube, and especially Wunderlich, in Germany. 

 These physicians were not content with proving that the tem- 

 perature in illness rises several degrees ; they followed the 

 variations of the thermometer day by day, hour by hour, in 

 the different phases of the pathologic movements. They 

 discovered that the curves of these oscillations furnish con- 

 stant types for each disease, which are modified in a reg- 

 ular manner, according as the disease has been left to itself 

 or treated by one or another medicine. By the study of 

 these pathologic curves of heat the course of diseases may 

 be followed, and valuable indications noted in diagnosis or 

 prognosis. In haemorrhage of the brain, for instance, the 

 temperature falls to 36 or even 35, while, in the attack 

 that takes the form of apoplexy, it continues nearly at 38. 

 These two disorders, quite distinct in their treatment and 

 cure, yet often give rise to a confusion, which the thermom- 

 eter will hereafter permit us to avoid. Granular menin- 

 gitis is distinguished from simple meningitis by the same 

 method ; in the former the temperature does not rise, not- 

 withstanding the extreme rapidity of the pulse, but in the 

 latter the thermometer marks 40 or 41. 



In every case we see what advantage practical medicine 

 may gain from the physical sciences, what precision and 

 safety it attains by the employment of its means, in pro- 

 portion to the morbid symptoms. We may add that the 



