- 1906] CURRENI LITERATURE 69 
HALsTED?’ has also issued a bulletin which gives a good general discussion 
of Mendelism as exemplified by cooperative experiments in the breeding of 
corn. In 1904 ‘Black Mexican” sweet corn was crossed with nearly a full 
list of the commercial varieties of sweet corn, and the hybrid ears thus obtained 
were sent to a number of volunteer observers in different parts of the state, who 
returned samples and notes which are incorporated into this bulletin. The 
presentation is simple and easily understood, but several unfortunate typo- 
graphical errors are likely to prove confusing, as when on p- 15 in the table show- 
ing what may be expected in the second generation of a cross between large 
grained flint black, and small grained sweet white, the fourth category (large 
sweet white) is weighted with the ae 9 instead of 3; and again, when on p. 21, 
line 7, “‘white” is used for “ dark.’ 
An improper emphasis is laid upon the difficulty of fivelig the dominant 
form from traces of the recessive. Thus, he says that after nineteen genera- 
tions of selection there will still be one recessive grain in each four hundred, 
adding that “this underlying rule,” which appears to hold more or less closely, 
helps to indicate how difficult it is to eradicate entirely any characteristic 
that has been introduced in breeding.” He seems -to have overlooked the 
importance of VitMorIN’s principle of isolation, by which it requires only one 
more generation to obtain pure extracted dominants than extracted recessives, 
So that after the third generation he need never have another recessive grain 
appear.—GEorRGE H. SHULL 
Inheritance in Shirley poppies—Prarson and his associates, with the aid 
of a number of volunteer observers, have presented a second paper?® on inher- 
itance in the Shirley poppy. Some of the questions that were left open in the 
earlier report?® have been settled. Thus, it was assumed that Shirley poppies 
both self- and cross-fertilize, and the discussions were based upon that assump- 
tion. It is now found that when flowers are enclosed in bags of bolting-cloth 
or oiled paper, almost no fertilization takes place. Fifty bagged flowers pro- 
duced seeds in only four, and these gave rise to nine plants. The conclusion 
is reached, therefore, that seeds taken from unprotected capsules are essen- 
tially the result of cross-fertilization; and the correlation of offspring with each 
other and with their antecedents should be the same as in other populations 
in which self-fertilization does not occur, as in animals and man. Although 
the correlation found is somewhat lower than the average for animals, a number 
of modifying factors are pointed out which would tend to lessen the correla- 
27 HALSTED, B. D., Bre eeding sweet comn—cooperative tests. N. J. Agr. Exp. 
Sta. Bull. ae pp- 30. pls. 4, figs. 8. March 19 
RSON, K., et al., Cooperative investigations in plants. . On inheritance 
n the Shirley poppy. - eres Memoir. Biometrika 4: 394-426. 1 = (colored). 1906. 
29 Pearson, K., et al., Cooperative investigation in plants. I. On inheritance 
n the Shirley Poppy. aan 2:56-I00, 1902. 
