METHODS 



113 



and so on indefinitely as long as there is life for Biology 

 has no Statics. 



The only relation which direct observation enables us to 

 verify between the cat's successive states A A and A 2 is this : 

 when the cat often exercises the function (A x B), it 

 becomes fitter to exercise the same function again. Always 

 the same law of habit which Lamarck took from the wisdom 

 of the nations the junction defines the organ ; the function 

 often repeated creates the organ. 



Let us take this observation into the field of colloid 

 mechanism. If at a point M of the body a protoplasmic 

 mass is made to execute several times in succession the 

 same operation of the mechanism as a whole, we under- 

 stand that it will be so modified by the operation itself 

 as to become fitter to exercise the same operation after- 

 wards. The case may be compared with that of proto- 

 plasmic elements struggling against a determined toxin 

 or food ; only, in the present case, the special function 

 of the protoplasmic mass is defined indirectly by the whole 

 mechanism of which it is a part. 



But in the adult animal protoplasmic masses localized 

 at different parts of the body are not subject, in their 

 relations with the whole mechanism, to such wide 

 variation as in their relations with toxins or foods. 1 

 We have seen the same protoplasm successively fabricate 

 antitetanus, antidiphtheria, etc., that is, in each case 

 carry on a specific struggle against a new enemy while 

 acquiring a new organ. It is not the same thing in the case 

 of protoplasmic masses considered as constituent elements 



1 It is true that, according to M. Metchnikoff, it is not the fixed 

 or constructive tissues which carry on the antitoxic defence, but 

 rather migratory elements, or phagocytes, having nothing to do 

 with the mechanism of the animal as a whole. 



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