PHYSIOLOGY, CHEMISTRY, AND MORPHOLOGY. 385 



coal to the work performed by a steam engine. By cooliug- the animal 

 we may extiuguisli the tire in the fiirua,ce; its functious are suspended, 

 but the mechanism that causes it to move is not, after all, destroyed, 

 for if we again heat the organism which we have beeu cooling it will 

 behave as the eugiue does when we relight its tire; the being on 

 which we are experimenting will again resume its movements. "If we 

 could," says Pictet,' "create an organized structure quite complete, 

 but dead, physicochemical conditions would be sufficient to develop all 

 the phenomena of vegetable life. Let us at once admit," he continues, 

 "that i)sychic phenomena could never be produced nor explained by 

 the simple movement of organized matter." It is a strange fact that 

 diastases and the poisons known as ptomaines, unlike organized matter, 

 appear to be much injured by great cold and lose their specific activities. 

 Thus low temperatures effect a remarkable distinction between microbes 

 and diastases, marking clearly the difference between chemical actions 

 under the influence of organization and those not so controlled. 



Let us further observe how processes which in the interior of living 

 tissues constitute the chemical basis of function, likewise occur exter- 

 nally in reactions which have their origin in life as well as in dead tis- 

 sues. These are processes that do not always lead to exactly similar 

 chemical results, but which have a similar general catabolic character 

 by which the very complex organic molecule, by means of oxidation or 

 successive divisions, by hydration or reduction, mounts the scale of 

 organic compounds and becomes by degrees more and more simple. 



The difference lies in this, that in living beings the kinetic effect 

 resulting from chemical affinity manifests itself in a thousand diverse 

 activities, while in dead tissues it is transformed almost wholly into 

 heat, other forms of movement, more particularly those of a func- 

 tional character, being totally arrested. 



This occurs because in dead tissues catabolic action likewise attacks 

 the structural mechanism, and this makes the working of the organic 

 machine impossible, while in the living organism the products that 

 by their decomposition induce functions are, under normal conditions, 

 almost wholly those inclosed within differentiated protoplasms, and if 

 sometimes this activity is also exercised upon the tissues, they are 

 rapidly and fully restored by metabolic processes. 



In short we ought to again recall that the chemistry of the tissues 

 not only supplies fuel for the mechanical substratum of our functions, 

 but is also used in constructing and restoring the organism. These 

 assimilating processes are controlled by the special elective attitudes 

 of each of the elements, and if they also have a chemical basis they 

 yet find their determining cause in a long history of external reactions 

 and internal adaptations by which is explained the gradual develop- 

 ment of living beings and the place which an organism has fixed for 

 itself in the hierarchy of organic forms. 



^Loc. cit., page 585. 

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