HEAT AND LIFE. 411 



suddenly to 3G 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 thermometer will hereafter allow to be avoided. Granular 

 meningitis is distinguished from simple meningitis by the same method ; 

 in the former the temperature does not rise, notwithstanding the ex- 

 treme 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 proportion to the morbid symptoms. 

 We may add that the future of diagnosis is to be found partly here. 

 By the banishment from medical examination of the often-uncertain 

 judgment of the senses, by substituting as far as possible for personal 

 and arbitrary 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 me- 

 thodical interpretation of the evil in question. Moreover, these in- 

 struments often reveal peculiarities that elude direct observation. 

 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 thermometer, of variations of animal heat in diseases, 

 thermometric clinic, as it is called, is one of the most indisputable 

 onward steps in medicine. 



III. 



After having seen how internal heat is produced in animals, how it 

 expends itself in them, and undergoes change into mechanical work, 

 in fine, what spontaneous or occasional changes it passes through in 

 them, we should study the influence of external heat on the same ani- 

 mals, and the various phenomena resulting from the rise or fall of tem- 

 perature in the medium they live in. Quite recent researches have 

 thrown light on these questions. Boerhaave had made some experi- 

 ments, 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 an- 

 imals in stoves containing air heated to different degrees of tempera- 

 ture, 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 du- 

 ration of resistance varies with the species. Small animals yield after 

 a moderate time to a temperature of 45 to 50 (cent.). Larger ones 

 endure heat better. Cold-blooded animals and the larva? of insects 

 resist more energetically than warm-blooded animals ; but the reverse 

 is the case with fully-developed insects. 



Delaroche and Berger studied the humau subject, too, from the 



