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THE AMERICAN NATURALIST [Vol. XLIII 



crystal, with new-formed angles. The analogy of repro- 

 duction with recrystallization is striking in many ways, 

 as we shall see farther. 



Thus inheritance is, here as elsewhere, not transmis- 

 sion but new production. The question of heredity then 

 is: What characters will thus be produced anew? Will 

 the progeny reproduce any character that the parent 

 happens to have? 



When we study the matter in such an organism as 

 Paramecium (Fig. 1), we find that all the characters 

 common to the race— the " normal" characters— are 

 regularly reproduced. But how about characters that are 

 not typical; characters that have been produced in the 

 individual parent by the environment; " abnormal' 1 char- 

 acters, and the like? It is easy to produce such new 

 characters by environmental action, and it is easy to 

 find in certain cultures individuals that present unusual 

 features. Specimens with altered form, with new ap- 

 pendages, with differently arranged parts, are not very 

 rare. Many of those found in natural cultures corre- 

 spond in appearance to what we might expect of a mu- 

 tation. 



Will such untypical characters reappear in the progeny, 

 so that we shall get a race with the new characteristic? 



Examination of a large number of cases in Paramecium 

 shows that these untypical characters are never repro- 

 duced in the young. Sometimes such a thing as an 

 appendage may pass bodily to one of the progeny, just 

 as a parasite clinging to the outer surface might do ; but 

 there is no multiplication of such a character; no tend- 

 ency to produce a race bearing it. The young reappear 

 in the form typical for the race, without regard to the 

 individual peculiarities of the parent. 4 



What is produced in the new generation therefore de- 

 pends on the fundamental constitution of the race, not on 

 the accidental form of the parent. Again the analogy 



*For many examples of this, with figures, see the first of the papers 

 •already referred to. 



