LAW OF INHERITANCE. 153 



beer, wherein all the sugar has been converted into alcohol 

 and carbonic acid, we have still another form, mycodiuua 

 acetis. 



Each cell appears to reproduce itself as it is at the time, 

 and we thus have development at corresponding periods. The 

 fitness of each portion of the body for its present requirements 

 is in this manner secured ; and on this principle of a like 

 inheritance can be explained the marvellous fact that each 

 portion of the body is adapted to its cooperation with other 

 portions of the body. Were distant progenitors as powerful 

 in their influence on the progeny as others more near, the 

 animal, instead of its present harmony of construction and 

 function, would be an inharmonious mass of independent 

 vitalities. We find, in accordance with this law, that in the 

 embryo, parts appear which are fitted for offices and relations 

 which are future. If, as appears to be the case, each cell 

 reproduces itself, and is also in turn affected by environment, 

 it would be in effect a denial of the persistence of force, as 

 Herbert Spencer observes, to expect that A can become A 1 , 

 and still produce the same progeny as if it were still A. 

 We may have, then, in a cell constant change, with a contin- 

 ual reproduction of the original, and thus a definite point may 

 be fixed, through inheritance from the past, for each cell to 

 acquire those functions for which it is suited. Adaptation, 

 therefore, comes through the influence of forces acting in the 

 past, and its presence is not only determinate, but is explained 

 by philosophy. 



As each cell reproduces itself as it is, including the varia- 

 tions brought about by inheritance and otherwise, it seems 

 reasonable to suppose that as all the body stands in relation 

 of environment to each cell, and produces changes which, in 

 turn, are transmitted, — cause and effect, persistence of force, 

 irrevocable laws, — so the spermatic cell has the power of trans- 

 mitting all the inherited variations brought about by the 

 totality of the individual, including his past. Inherited 

 variation or persistence of force seems a more philosophical 

 hypothesis, nay, I will say theory, than pangenesis. 



In those cases of repair after injury, as is noticed by Paget, 

 in an adult animal, when a part is reproduced after injury, it 

 is made in conformity, not with that condition which was 



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