Production of California Grapefruit 
attempts were naturally in the direction 
of codperative marketing. Extension 
of this coéperation to the improvement 
of varieties and breeds will have com- 
mercial results that can hardly be 
overestimated. Some of the live-stock 
breeders already have their ‘“‘circuit 
bulls;’ many have milk or butter-fat 
527 
tests. Horticulturists are in the nature 
of things enabled to proceed even more 
rapidly, and the radical action of the 
California grapefruit growers will un- 
doubtedly be followed by other branches 
of agriculture, as fast as the progress of 
genetics marks the way. 
Another German Proposal to Increase the Birth Rate 
A. Zeiler in Die Grenzboten (March, 
1916) says in sum: The serious danger 
of being outnumbered by our eastern 
neighbors must be averted at all risks. 
Since the rising standards of living 
make large families nearly impossible, 
and since the gap between the mode of 
living of the unmarried or childless 
and the large family are the strongest 
reasons for a decreasing birth-rate, large 
families must be encouraged’ through 
economic assistance. A bachelor tax 
alone is inadequate, and the disad- 
vantages of exemptions from taxation of 
heads of families are greater than the 
advantages. Only a proper balancing 
of the family burden through a general 
and. proportional subsidy or pension 
will really help. These subsidies must 
be large enough to be effective and yet 
not so large as to eliminate the very 
principles upon which the family rests: 
the sense of responsibility and the 
willingness to sacrifice. The subsidy 
should be in the form of a gift for the 
girl who marries; annual contributions 
to the expenses of every home, whether 
there are children or not; and a grant 
for every child, graded according to 
age and education received. A tax 
amounting to about 3% of the total 
income, after an absolute minimum and 
a proportional subsidy had been de- 
ducted, would furnish the funds. A 
bachelor, the head of a family without 
children, and the head of a family with 
five children and an income of 4,000 M.., 
for example, would pay a tax of 816 M. 
The childless family, however, would 
receive a compensation of 600 M. per 
annum, the family with five children 
not over 14 years of age, an additional 
sum of 712 M., while the bachelor 
would receive no compensation what- 
ever.—Abstract in American Journal of 
Sociology. 
Ewing’s Study of an Aphis 
. Having bred a plant-louse (Aphis 
avenae Fab.) for eighty-seven genera- 
tions, Prof. H. E. Ewing describes his 
study in the Biological Bulletin, XXXI, 
2, pp. 53-113. The insects formed a 
parthenogenetic pure line, in which six 
different fluctuating variations were 
marked. Selections were made for ten 
or more successive generations in the 
case of three of these characters; for 
forty-four successive generations in one 
character; and were carried out in both 
plus and minus directions in the case 
of two characters. In all of these cases 
no summation of effect was produced by 
selection. The writer concludes, there- 
fore, that such variations are not due to 
the germ-plasm. “The ~pure line 
theory,” he holds, ‘“‘applies to partheno- 
genetic arthropods as well as to forms 
that reproduce by budding, fission, or 
self-fertilization,”’ but he points out 
that it is a great mistake to attempt to 
apply it to animals that reproduce 
sexually. A few abrupt variations were 
noted, but were not found to be inher- 
ited any more than the small fluctua- 
tions which were continually occurring. 
