Ewart— Variation: Germinal and Environmental. 359 
from the most docile and most fertile members of their flocks and herds, 
the tamest and least nervous of their rabbits, pigeons, &c., and the fleetest 
or keenest scented of their hounds, and not because acquired variations are 
transmitted. 
If definite acquired variations are not transmitted in cultivated plants or domestic 
animals, it is inconceivable that they are transmitted in human beings, that the 
higher branches of the human family owe any of their finer traits (aptness to 
acquire knowledge and the like) to the gradual accumulation during many 
generations of specific somatic (non-germinal) variations. 
(2). The influence of nutrition and somatic well-being on the germ-plasm. 
If it is impossible to endow the offspring with special somatic characters or 
traits acquired in virtue of a heritage of individual plasticity, let us see whether 
there is any evidence that the germ-cells more or less accurately reflect the 
condition or general fitness of the individual in which they are formed, as buds 
bear an intimate relation to the plant on which they grow. Though there is no 
evidence that the blacksmith can endow his children with a strong right arm, there 
may be good reasons for believing that the germ-plasm of a mature, vigorous, 
healthy individual, is likely, other things being equal (e.g. the prepotency), to 
overcome, during the conjugation of the germ-cells, the germ-plasm of a less 
matured and less mentally and physically fit individual. Ifit can be shown that 
the germ-plasm not only in a way reflects the vigour or general fitness of the 
somatic tissues, but also that the condition (e.g. ripeness) of the germ-plasm to a 
certain extent determines the nature of the combinations formed during conjuga- 
tion, and also whether the male or female parent will control the development, it 
will be evident that the environment is indirectly an important factor in causing 
variation, without which progressive development is impossible. 
I find some horses, colts as well as fillies, mature sooner than others; that most 
horses reach maturity sooner than zebra-horse hybrids, and that hybrids mature 
sooner than zebras. Again I find that the cross-bred offspring of pigeons obtained 
in the early spring differ in various ways from birds bred during summer. In the 
case of fillies, the ones kept indoors and well fed during the winter reach maturity 
sooner than the fillies infested with the parasite strongylus, or allowed to run out all 
winter. Further, while there are often signs of ovulation in stall-fed mares all 
through the year, mares only receiving hay, and the occasional shelter of a shed 
during winter, may only begin to show signs of ovulation in April or May. Again, 
animals in too good a condition, like animals out of condition, owing, ¢.g., to a 
change of habitat, are often, at least for a time, sterile. 
