No. 3-] EXPERIMENTS IN BREEDING MKi:. 127 



Several remarkable things come out of this table. In the 

 first place the most marked departure from Gallon's Law of 

 Ancestral Inheritance is seen in the second generation, where 

 the gray, non-walzing reversions suddenly made their appear- 

 ance. We know as yet little concerning the laws of the phe- 

 nomenon called "reversion"; but whether it be considered a 

 remote atavism or only an apparent "inheritance," it seems 

 equally to form an exception to Galton's Law. 



Secondly, the case of the walzers does indeed look like an 

 exception to Galton's Law. It looks as though the walzing con- 

 dition were an unstable condition being rapidly eliminated. In so 

 far the result opposes the usual expectation of sport prepotency. 



Thirdly, the albinos, likewise sports, apparently are pre- 

 potent, since there is twice the proportion there should be in 

 the sixth generation. The numbers are so large that one can 

 hardly object that these figures are not altogether significant. 



Fourthly, the grays run close to theory, excepting always 

 generation II. They are nearest to the original type of Mus 

 muscnlns and seem to inherit in the most nearly normal 

 fashion. 



In conclusion, then, we may say that the data afforded by 

 these breeding experiments indicate, so far as they go, that 

 Galton's Law of Inheritance holds only with form units which 

 are not very divergent from the type, and that among sports 

 we may have some that show a great stability and prepotency, 

 while we may occasionally have others which are physiolog- 

 ically so unfit that they are unstable and have less than normal 

 potency. 



