An Introduction to a Biology 



00 00^ 



CO, 



00 CO oc 



00 00 CO OG oc 



Now let us consider the generation, produced by mating 

 the hybrids, from the point of view of its progression. Less 

 than a quarter of them waltz. But the deficiency is prob- 

 ably due to the fact that ■ waltzers are constitutionally weak 

 creatures and are more likely to die before they reach the 

 age at which their characters can be recorded than other 

 mice are. What is of interest is that the waltzing habit is 

 not necessarily associated with that colour character OC 

 with which it is associated in the pure strain, but is distri- 

 buted at random over the three categories 00, OC, and CC. 



We have so far confined ourselves to the description of 

 phenomena. Now let us consider two theories which have 

 been put forward to account for them ; first, one by Von 

 Guaita associated with the name of Weismann, and secondly, 

 one by Bateson associated with the name of Mendel. 



The theory suggested by Von Guaita was intended to 

 account for the results of a hybridisation experiment (similar 

 to mine except for the fact that his waltzers had black eyes) 

 carried out by himself. 



He suggested that there were two kinds of factors in a 

 germ-cell that gives rise to an albino ; one, which we may 



* It may be objected that I have introduced an element of confusion 

 by representing one homozygote by two similar letters, the other by two 

 different ones, and the heterozygote by two similar ones. But this objec- 

 tion is successfully met by saying that my formulae can only lead to con- 

 fusion among those students who have not been taught that such formulae 

 are nothing more than conceptual descriptions of features of the germ- 

 cells which we have not yet perceived. And such beginuera will be confused 

 anyhow. 



o 209 



