486 GENETICS IN RELATION TO AGRICULTURE 
saved. . . . Like the other three young they were black, but with a few red 
hairs among the black ones. They bore no white hairs. 
Female 1970, daughter of the grafted albino, was mated with the albino male, her 
father,-and bore three young, two of which were albinos and one black with some red 
hairs. If female 1970 had been the daughter of a pure-black mother, instead of a 
grafted albino, we should have expected her to produce an equality of black and of 
albino young. The observed result was the nearest possible agreement with this 
expectation. 
A control mating of the albino male, 654, was made with a female of pure-black 
stock. Asa result there were produced two litters of young, including five individuals, 
all black, with red hairs interspersed. This result shows that the red hairs found on 
the six young of the grafted albino was due, not to foster-mother influence of the 
grafted albino, but to influence of the male parent. The young of the grafted mother 
were exactly such in color as the black guinea-pig which furnished the graft herself 
might have been expected to bear had she been mated with male 654 instead of being 
sacrificed to furnish the graft. The white foot borne by one of the young furnished no 
exception to this statement. Spotting characterized the race of guinea-pigs from 
which the father came. He was himself born in a litter which contained spotted 
young whereas neither the pure-bred black race that furnished the graft nor the albino 
race that received it was characterized by spotting. 
Inasmuch as the offspring of albino parents are invariably albinos, it is certain 
that the six pigmented offspring of the grafted female were all derived fromova 
furnished by the introduced ovarian tissue taken from a black guinea-pig. This tissue 
was introduced while the contained ova were still quite immature, and it persisted 
in its new environment for nearly a year before the eggs were liberated which produced 
the last litter of three young. These young, like the earlier litters, gave no indication 
of foster-mother influence in their coloration. 
The conclusion is forced upon us that the egg-cell during its growth 
does not change in germinal constitution. Its growth is like the growth 
of a parasite or of a wholly independent organism: what it takes up serves 
as food; this is not incorporated merely in the growing organism, it is 
made over into the same kind of living substance as composes the assimilat- 
ing organism. Thus a critical experiment designed to test the relation 
of soma to germ cells with respect to coat coloration failed to demonstrate 
any direct interrelation whatever, and further experiments by the same 
investigators indicated that for other factors also the foster-mother 
exerted no influence whatever on the developing ova. The ovary of the 
black guinea-pig produced exactly the same kind of ova in the body of the 
albino as it would have produced had it remained in the body of the black 
guinea-pig. Figs. 192 and 193 show the nine animals reported in this 
experiment. The full record of this experiment of Castle and Phillips’ 
shows in detail the character of critical investigation which has been 
brought to bear on various phases of the question of the inheritance 
of acquired characters. 
In passing, it should be mentioned that a few previous experiments 
on germinal transplantation appeared to indicate the existence of some 
influence of the foster-mother. Of these the experiments of Guthrie on 
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