Studies of Teratological Phenomena. 123 



of this cross, it is held that only one factor is involved, and if that 

 factor is present in a chromosome, it is in duplex condition in each 2n 

 cell and simplex in each n cell. All anthers and other organs are held 

 to be gametically similar in such a race, and every cell, except for 

 environmental modifications is identical with every other cell of the 

 organism. Pollen mother-cells are identical as to factor composition and 

 can differ from one another onlj^ in environmental modifications. 

 Environmental conditions must be practically the same in the same 

 anther and in all the anthers of a single bud. The questions then 

 arise why the factor A is latent in some cells and patent in others, 

 and why a certain definite percentage of each anther's pollen is not 

 aborted rather than all of it, etc. ^). From these data, one would find 

 no support for the chromosome hypothesis of inheritance and in theory, 

 there is directly opposing evidence. 



14. Three other crosses were made, the Fi plants of which were 

 fertile. One of these (301 — 1 — 5X373) did not appear to differ much 

 from 402 or 300 — 309 in factors affecting height, though in other 

 respects the factorial complexes of the two varieties were very 

 different. Tliis was even more true of the varieties 353 and 396, as 

 they were branching, shrubby, dwarf-statured plants. When crossed 

 with 300 — 309 and the F2 generation observed, it was very evident 

 that the latter variety differed from the two former in an exceedingly 

 large number of characters (factors). The crosses of 396 with 301 

 demonstrated the extreme extent of these differences, as hardly any 

 two plants were alike among the whole 477 F« progeny, and many 

 of their distinguishing features were sharp and clear-cut genetic 

 characters. 



15. The ratio of abnormal to normal plants in these three crosses 

 was very confusing, as in all cases, there was excess of "somatic" 

 normals and this divergence from the theoretical expectancy increased 

 as the apparent character differences between the two grandparents 

 became more numerous. In 301 — 1 — 5 X 373, the excess of normals 

 above the expected was only 2*8 per cent; in 353 X 301 — 1, the excess 

 rose to 4-8 per cent, while in 396X301 and reciprocal crosses, the 

 increase in normals over the theoretical had mounted to 9*7 per cent 



^) Attention is called to the similarity between the disturbances and modifications 

 produced by the factor A, and that caused by certain parasite mutilations. All the 

 experimental data are opposed to the theory that the factor A is an internal parasite 

 foreign to the organism. 



