INEQUALITIES IN HOMOLOGOUS CHROMOSOMES 129 
lf the basis of albinism le in an abnormal reduction division 
of a certain pair of chromosomes, we should expect it to do just 
that sort of thing. So long as the same number of pairs of chro- 
mosomes occurs in a species, so long will the same variations 
continue to occur. In this way we shall continue to have white 
animals produced anew by ‘mutation’—blacks, yellows, spotted, 
and all the varieties not only of color but in respect to other 
properties of the body as well. In the same way we might al- 
ways expect to have produced a certain percentage of defective 
human beings, such as the classes of feeble-minded, imbeciles, 
epileptics, etc., each of which seems to be due, in many cases 
at least, to something lacking in the germ plasm (Davenport ’11). 
Germinal variations of this kind, it seems to me, might be at 
the basis of De Vries’ ‘eversporting varieties,’ which gave such 
abnormalities as striped flowers, five-leaved clovers and mon- 
strosities of various sorts, such as pistollody, twisted and flat- 
tened stems, etc. Again, it seems possible that germinal vari- 
ations of this sort might lie at the basis of those of De Vries’ 
mutations which he distinguished as retrogressive in character; 
i.e., which were characterized by the dropping out of some 
character from the parent species. They might lie at the basis 
of some mutants which he considered progressive, but which 
showed some retrogressive traits, such as the brittleness of the 
stem in Oenothera rubrinervis. My reasons for supposing this 
are as follows: De Vries found his ‘eversporting varieties’ pro- 
ducing their abnormal individuals continually. He found his 
parent species, Oenothera lamarckiana, continually throwing 
off the same mutants in certain proportions. ‘‘No single parent 
plant proved ever to be wholly destitute of mutability.’’ In his 
parent species, lamarckiana, he has probably a constant funda- 
mental number of chromosomes to deal with. He has a reduction 
division taking place every time a germ cell is formed. He has 
the same possibility of abnormal, unequal, divisions of tetrads 
at the time of this division, giving a deficient homologous 
chromosome. He has self fertilization (inbreeding), which would 
tend to bring such defective chromosomes together. He has 
frequent cases of sterility in the inbred offspring of his mutants, 
