xix HEREDITY 371 



inexperienced eye all the individuals may seem alike. 

 This is one extreme. 



The other extreme is seen when an offspring is born that 

 is in sonic feature or features very unlike its parents and 

 kindred, exhibiting some novel pattern, some new position 

 of organic equilibrium, in technical language a mutation 

 or discontinuous variation. Such new departures have 

 sometimes formed the beginning of a iiew r domesticated 

 breed or cultivated variety ; and it is possible that new 

 species in nature may sometimes have begun in this way. 

 In mankind these mutations are illustrated by mathe- 

 matical and musical geniuses, by children with marked 

 originality, and by less desirable idiosyncrasies. The con- 

 ditions of their appearance are not known. 



Between the two extremes that we have mentioned there 

 are two main modes of inheritance, which are contrasted 

 as blended and alternative (or Mendelian), and there 

 are many who think that what seem to be blends will 

 eventually turn out to be complicated cases of Mendelian 

 inheritance. Taking things as they are, however, there 

 seem to be cases where the offspring as regards certain 

 features exhibit what may be called an intimate blend 

 of the paternal and maternal characteristics. Thus, 

 though the case is not so easy as it seems, a mulatto is 

 often regarded as illustrating in the colour of his skin a 

 blending of paternal and maternal characters. Dr. E. 

 Warren has described two hybrids between two kinds of 

 cockatoos Cacatua galerita (male) and Licmetis nasica 

 (female), which appear to show a blending of the char- 

 acters of the two parents. Out of ten characters the 

 hybrids were nearer Cacatua in five, nearer Licmetis 

 in one, and almost exactly intermediate in four. In 

 every character examined, with the possible exception 

 of the coloured and non-coloured lores (the space between 

 the bill and the eye), there was a very obvious blend- 

 ing of the paternal and maternal characteristics. In a 

 cross between a long-eared lop rabbit and a short-eared 

 breed, Prof. Castle found that the offspring were inter- 

 mediate in length of ears and in skeletal measurements, 

 and that they bred true. 



