1914] CURRENT LITERATURE 243 
the language is so technical that transmutations must be made before an ordi- 
nary biologist can understand it. When the F, plants derived from the crosses 
(BXG and GX B) were back-pollinated with B and G, their behavior in refer- 
ence to seed-setting indicated that they could be separated into four more or 
less distinct classes: (1) plants fertile with both B and G; (2) plants sterile 
with both B and G; (3) plants fertile with B, but sterile with G; (4) plants 
sterile with B, but fertile with G. Numerically, the 60 F; individuals were 
found to distribute themselves among the four classes in about equal propor- 
tions, the actual numbers being 16 bg:16 bG:14 Bg:14 BG. 
Crosses between the individuals of these four F, classes, 720 of which were 
made, in the main confirmed the results obtained through back-crossing with 
the parents. Crosses between different F, plants and plants obtained from 
foreign sources all resulted in well-filled capsules. From the facts presented, 
the conclusion that two inhibitors were operating to present self-fertilization 
Was a most natural and simple interpretation. Accordingly, CoRRENS gives 
to those F, plants fertile with both B and G, the formula dg, indicating the 
absence of both inhibitors; those plants fertile with one parent and sterile with 
the other are either Bg or bG, indicating the absence of one and the presence of 
the other inhibitor; and lastly, those plants sterile with both B and G are said 
to be BG, indicating the presence of both inhibitors. CorrENs does not dog- 
tize as to the nature of these inhibit except to say that they are hereditary 
constituents of the germ plasm, which appear to segregate in Mendelian 
fashion some time prior to the complete development of the egg cells and pollen 
grains, Hence, self-sterility is not a phenomenon of “Individualstoffe” in the 
Sense in which this term was used by Jost. 
In Correns’ scheme of interpretation, his two original plants are hetero- 
zygotes, B represented as Bb and G represented as Gg, the letters indicating 
the Presence and absence of two distinct factors for self-sterility. Bb gives 
rise to two kinds of gametes, those with the inhibitor (B) and those without 
It (b). Gg likewise produces gametes with G and gametes from which it is 
absent (g). Bbx Gg is fertile, but neither Bb Bb nor GgXGg would result in 
seed-formation, as the presence of the factor B would inhibit the growth of the 
Pollen from the Bb type. The same is true regarding plants of the Gg type. 
The cross BbX Gg results in the four types BG, Bg, bG, bg, the classes actually 
tained as ascertained by the pollination tests. Types BG, Bg, and 0G are 
self-sterile, while type bg should be self-fertile. Plants of the bg type should 
be fertile with the other three types; type bG is fertile with only Bg; type 6G 
with only Bg; while BG is fertile with only bg. It is obvious that types BB 
and GG could never be formed. 
Correns’ interpretation of his results opens itself to numerous criticisms, 
for even the most ardent supporter of Mendelian universality would question 
the actuality of the four classes. Neither the data from the back-pollination 
“xperiments nor the data from those in which F, sisters were crossed give any 
notion of clear-cut classes, such as MENDEL secured in his pea work. For 
