in its Relations to Physiology. 423 



I can determine, with the most positive certainty, the amount of 

 alcohol necessary to heat a given amount of water or of iron and to 

 maintain it at this temperature for a certain definite time ; now, if iu a 

 stove or furnace altogether inaccessible to me, but provided with an 

 aperture for the reception of the fuel, and another for the exit of the 

 products formed by the combustion of this fuel, I find that these pro- 

 ducts consist of carbonic acid, water, and ammonia, and that the con- 

 version of the fuel into these compounds depends upon a constant 

 supply of atmospheric oxygen, can I rationally and logically ascribe 

 the higher temperature which I perceive iu this stove or furnace to any 

 other cause than that which I see producing the same effect in an 

 accessible furnace ? Are my conclusions to be deemed fallacious because 

 they do not explain the manner in which heat propagates itself in the 

 water, or in the iron, or in the inaccessible stove, i. e., in the organism? 

 I never intended to explain from what cause, or in what manner, the 

 head becomes heated when the feet grow cold, although it is quite in 

 accordance with my views that heat should accumulate in one place 

 when its diffusion in other parts is impeded. 



I know an individual whose head grows cold as ice when his mind is 

 affected by any strong emotion, while his feet, at the same time, be- 

 come glowing hot, but I do not think myself justified on that account 

 to place the seat of the evolution of heat in the lower extremities.* 



Questions relating to the distribution of heat in the animal body, and 

 innumerable others relative to the processes and actions of the constitu- 

 ent parts of living organisms, we may properly anticipate will be an- 

 swered hereafter — time only is required for the solution of many un- 

 solved problems. What is chiefly needed at present is the determination 

 of principles, the settlement of methods for the pursuit of investigations. 

 So long as physiologists and pathologists (the latter are the more 



* Thus I read in a work on physiology, published some time ago, a very insulting commen- 

 tary on the following sentence in my " Chemistry applied to Physiolgy and Pathology :" — " The 

 only known and ultimate cause of the vital activity in the animal organism is a chemical pro- 

 cess." The words only and ultimate were in italics, as they are here, but the preceding and 

 succeeding sentences were altogether omitted. The former sentence says,—" We recognise in 

 the animal organism only one cause as the ultimate cause of all production of energy, and this 

 is the mutual action which the constituents of the aliments and the oxygen of the air exercise 

 upon each other." The succeeding sentence continues, — "If we exclude the chemical pro- 

 cess, that is, the air and water, in the germination of seeds, or the air in the respiration of 

 animals, the manifestations of life take place no longer, or they cease to be perceptible." 

 What I intended to say here must be obvious to every one; I might indeed, have underlined 

 the word known, and might perhaps, have substituted condition for cause. But who would 

 have thought, after reading my book through, that any one could be in doubt with regard to 

 my views respecting the cause of the vital phenomena I 



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