292 THE GERM-PLASM 



horses owe their superiority to three individuals, — viz., to the 

 Turkish horse ' Byerley,'' and the Arabs ' Darley ' and • Godol- 

 phin ' ; and the celebrated race of Orlow trotters can be traced 

 back to the stallion ' Bars the First.' 



If these animals really possessed a stronger ' force of heredity ' 

 in the sense indicated, it must not be confounded with the 

 property oi faitJtfitl transmission in a race. This property of 

 ' breeding true ' must be due to the presence of a large majority 

 of homodynamous determinants in the germ-plasm, or, what 

 amounts to the same thing, to the existence of similar, i.e.. of 

 'racial,' determinants for every character in most of the ids. 

 The longer a pure race has been kept up, all the individuals 

 which exhibit variations being carefully eliminated, the greater 

 will be the number of ids containing ' racial ' determinants, and 

 the more rarely will variations appear in individuals. 



At present, however, we are concerned with individual, and 

 not with racial characters. These cannot possibly have been 

 contained in a preponderating majority of the ids of the germ- 

 plasm from which the individual arose, for the germ-plasm is 

 composed of paternal and maternal ids. The transmission of 

 the proper ' type ' can in this case therefore only be due to the 

 fact that the group of idants which preponderated in the devel- 

 opment of the parent is once more present in the germ-cell. I 

 should consequently prefer to account for the so-called pre- 

 potency in transmission by assuming that in some individuals 

 the reducing division simply occurs in such a manner as to 

 separate the paternal and maternal groups of idants, while 

 ordinarily it results in combinations of idants of all kinds. 

 It is impossible to say at present on what peculiarity of the 

 idants themselves or of the apparatus for nuclear division, 

 this must depend ; but it can at any rate be stated that the 

 dominaat group of idants cannot possibly be contained in every 

 germ-cell of such an individual, even in the most favourable 

 case. On the contrary, it can only be present in half of them ; 

 for, according to our assumption, the reducing division always 

 causes the dominant group of idants to pass into one of two germ- 

 cells only, the subsidiary group passing into the other. This 

 supposition is in accordance with the facts ; for, so far as I 

 know, it has never been observed that all the offspring resemble 

 the parent which exhibited ' individual prepotency,' but this, on 

 the contrary, was only the case as regards some of them. In 



