MarcH 1, 1912] 
other tremendous advantage is gained by 
going to the trouble of making separate pedi- 
gree cultures of the various lines, thus admit- 
ting an analysis of results, such as was some- 
times impossible in the case of the work of 
previous investigators in this field. 
Part II. deals with endosperm characters, 
and under this subject is taken up first the 
transmission of starchiness of endosperm. 
Although the behavior of this character as to 
dominance and segregation is already known, 
the matter is made the subject of an unusually 
thorough and critical study here because of 
the sharpness and completeness with which 
starchiness segregates and with the idea of 
applying this study to some fundamental prin- 
ciples in their connection with Mendelism, 
such as prepotency and gametic purity. In 
all the large number of cases examined the 
behavior in this respect is found to be so 
regular as to force the conclusion that “ the 
mechanism by which the members of an al- 
lelomorphie pair are distributed among the 
gametes is accurate,” and none of the extra 
explanations offered by some other investi- 
gators to account for discrepancies are needed 
here. 
In connection with the transmission of yel- 
low and non-yellow endosperm, an important 
principle is brought out; namely, that in cer- 
tain strains of corn yellowness is not a simple 
unit, but rather is the result of two distinct 
and independent yellow units or factors oper- 
ating to give precisely a di-hybrid effect. 
This is an important observation, in that the 
same principle may be carried to various other 
characters supposed to be simple, but which in 
reality may prove, upon more critical analysis, 
to be compound, depending upon the operation 
of a series of units or factors. 
The transmission of endosperm colors has 
been left rather vague by the experiments of 
previous investigators in this field. Some of 
the discrepancies in the results of Correns and 
of Lock with respect to the behavior of purple 
aleurone colors are now explained by the 
present investigation; thanks to the separate 
pedigree culture making possible a more thor- 
ough analysis of data. It is found that the 
SCIENCE 
343 
behavior in this regard is not always constant, 
but varies in different strains or families, 
apparently depending upon the constitution of 
the uniting gametes. The conception of cer- 
tain developer and inhibitor factors serves to 
explain quite satisfactorily most of these cases, 
and it is believed that when all of the facts 
are known, most, if not all, of these discrepan- 
cies and contradictions will be similarly ex- 
plained, and thus will be wiped out some more 
of the seeming exceptions to the law of 
Mendel. 
Part III. is a discussion of Xenia and the 
observations here are in the main in accord 
with those of previous investigators. On ac- 
count of the various effects of dominance in 
different cases some confusion has arisen con- 
cerning this phenomenon. An explanation of 
these cases is given in connection with which 
the following law regarding Xenia is formu- 
lated : 
“When two races differ in a single visible 
endosperm character in which dominance is 
complete, Xenia occurs only when the domi- 
nant parent is the male; when they differ in a 
single visible endosperm character in which 
dominance is incomplete or in two characters 
both of which are necessary for the develop- 
ment of the visible difference, Xenia occurs 
when either is the male.” 
In Part IV. is considered the inheritance 
of a number of plant characters. In the case 
of the podded kernel the presence of pods is 
found to be a perfect dominant. In the in- 
vestigation of pericarp colors a number of 
different kinds of reds are distinguished. Red 
in cob color was found to behave as a simple 
character in the cases examined, but red color 
in silks appears to be more complex in its 
inheritance. 
A section is devoted to the matter of phys- 
ical transformation of starchiness, and a 
study of the crosses between soft starchy and 
corneous starchy sort brings out the follow- 
ing three facts: “ The characters that give the 
flint or the dent appearance to maize are 
transmitted as plant characters to the entire 
ear and not as endosperm characters to the 
individual seed. They conform to the essen- 
