B38 HEREDITY. 



cells of the ovary and the testis. At the moment of the formation 

 of ova and spermatozoa, for some nnknown reason, the two potencies 

 can not remain longer in the same cell; the}^ separate from each other; 

 there is, as is said, a disjiuicfio?i of cliaracters. Half of the gametes 

 receive the gray character (G), the other half the white character 

 (B). When these hybrids are crossed with each other there may 

 consequently be produced four combinations of gametes: 



Gray X Gray (GG) 

 Gray X White"! .^-gN 

 White X Gray V ' 

 White X White (BB) 



These four combinations will give the following results : 



Gray X Gray = Gray of pure race. 

 ofGray X White! = Gray of impure race, similar to the hybrids of the first genera- 



l White X Gray J tion. 



1 White X White = White of pure race. 



We may express this result in a briefer form b}' saying 

 GB X GB = 1 GG + 2 GB + 1 BB. 



Avhich corresponds to the results of the experiment. 



On the other hand, we may verify, one by one, the mice produced 

 and see that ever3'thing conforms entirely to the theoretical explana- 

 tion. The diagram (fig. 2) shows one of these verifications. By 

 crossing a gray mouse of impure race, which includes the white in a 



dominated state, with another white 



mouse, there is obtained this time as 



many whites as grays. In fact, because 



of the disjunction of characters the mixed 



hybrid produces as many gametes having 



^K\ r~^ a gray character as gametes having a 



^K/ V_y white character. The white mouse nat- 



\ / B iirally possesses only gametes having a 



\,^_ white character. There are, then, only 



^^>. ^MrN ^— N /-^ two combinations possible — 



^fgJ^St) V_y V ' ^^1"^^' X Clray = Gray of impure race (GB). 



GB GB BB BB White X White = White of pure race {V,^). 



Fig. 2. — Diagram of a crossing be- Ihen — 



tween a gray mouse possessing the GB X BB = 1 GB + 1 BB. 



white character In a latent state 



and a white mouse. The progeny The experiments, Very loug and often 



show an equal number of grays and q^^^^g delicate, give rCSults SO mUch in 

 whites. ^ . . 



conformity with the theoretic anticipa- 

 tions that it is evident that the hypothesis represents the real con- 

 ditions. It has been proved that this curious phenomena of the dis- 

 junction of characters, resulting in the purity of the gametes^ is 



o 



