146 NATURE AND LIFE. 



future of diagnosis is to be found partly here. By the ban- 

 ishment from medical examination of the often-uncertain 

 judgment of the senses, by substituting as far as possible 

 for personal and arbitary conclusions, as well as for the 

 feeling, always more or less confused, of the physician, the 

 plain and impassive indications of an exact instrument, we 

 do away with the causes that impede the methodical inter- 

 pretation of the evil in question. Moreover, these instru- 

 ments often reveal peculiarities that elude direct observa- 

 tion. They repair the omissions, correct the mistakes, 

 guide the activity, multiply the power of our imperfect 

 senses. From this point of view, the study, by the ther- 

 mometer, of variations of animal heat in diseases, ther- 

 mometric clinic, as it is called, is one of the most indis- 

 putable onward steps in medicine. 



III. 



After having seen how internal heat is produced in ani- 

 mals, how it expends itself in them, and undergoes change 

 into mechanical work, in fine, what spontaneous or occa- 

 sional changes it passes through in them, we should study 

 the influence of external heat on the same animals, and the 

 various phenomena resulting from the rise or fall of tem- 

 perature in the medium they live in. Quite recent re- 

 searches have thrown light on these questions. Boerhaave 

 had made some experiments, not sufficiently exact, however, 

 on the subject. Berger and Delaroche, at the beginning 

 of this century, undertook new ones, which gained celebrity 

 in the schools of physiology. They placed animals in stoves 

 containing air heated to different degrees of temperature, 

 and noted the effects produced on life by thermic influences. 

 The conclusion from their researches was, that all animals 

 have the power of resisting heat for a certain length of time, 

 and that the duration of resistance varies with the species. 

 Small animals yield after a moderate time to a temperature 





