INHERITANCE OF ACQUIRED CHARACTERS 97 



go to show that cultures of bacteria may, under altered 

 conditions, undergo transformations which are maintained 

 through a series of generations, though the inducing con- 

 ditions may long since have ceased. The fact is that 

 unicellular organisms are modified under the direct influ- 

 ence of the environment, but the inheritance of such 

 modifications is not comparable with that in multi- 

 cellular beings. The change which is wrought in the whole 

 body of the unicellular organism is naturally transmitted 

 to the next generation, because this really is nothing but 

 the mother-organism divided into two halves — soma as 

 well as nucleus. There is no differentiation as yet between 

 body and germ cell. A metazoon derived by a series of 

 cell divisions from a single cell is strictly comparable, not 

 to one generation of one-celled animals, but to a number of 

 such. The process of inheritance involved is, therefore, 

 a different one. In short, while there is inheritance of 

 acquired characters in unicellular beings, this proves nothing 

 for the case of multicellular organisms. Or we can look 

 upon the matter from another point of view, and express 

 the problem in the following way : In one-celled organisms, 

 body and germ being one, acquired characters are at the 

 same time inborn characters ; both kinds of inheritance, 

 somatogenic and blastogenic, are not yet differentiated. 

 In higher animals the problem of acquhed versus inborn 

 characters is set for the first time. 



(b) Mutilations. 



It used to be a favourite argument of the defenders ol 

 the affirmative side to quote cases of mutilations which 

 had been inherited, and were therefore considered incontro- 

 vertible proof in favour of their contention. Thus, a cat 

 had accidentally lost her tail, and given birth to a tailless 

 kitten ; and similar cases of that sort. It has been found 

 that none of these cases could stand scientific examination. 

 Even where mutilation has been practised for ages for 



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