THE QUADRUPLETS AND THEIR MOTHER 
Mrs. Keys is 35 years old and weighs about 150 pounds. 
She has borne four children previously. 
The quadruplets, until they were nine months old, had no other food than mother’s milk. 
This photograph, showing themat the age of one year (arranged in the same order as in 
Fig. 10) is copyrighted by F. M. Keys. 
has explained the occurrence of pota- 
toes with white skins. ! 
The tuber of the wild potato has a 
purple skin, but in cultivation nowa- 
days we find two types, one with a purple 
skin and the other with a white skin. 
The latter corresponds to albino forms 
of other plants; it is ight colored merely 
because the agent that normally pro- 
duces pigment is not present. 
East found, as a result of inquiries 
and of his own breeding experiments, 
that colored skin and white skin formed 
a contrasted pair of Mendelian char- 
acters. Color was dominant, and the 
white skin could appear only if color 
was lacking. If a colored potato and 
a white potato were crossed, the off- 
spring were all colored; on the other 
hand when a white-skinned variety was 
propagated asexually, by its tubers, it 
(Fig. 11.) 
remained white generation after genera- 
tion. 
But when a purple-skinned variety 
was propagated by tubers, it did not 
invariably remain purple, generation 
after generation. All of a sudden, the 
purple might disappear, and one or 
more plants would be turned up with 
white-skinned tubers. 
Propagation being asexual, this loss 
of color could not be due to hybridiza- 
tion. It is the kind of a change which 
goes under the name of bud-variation, 
and East decided that it represented the 
dropping out of the character “color” 
at some time when the vegetative cells 
of the potato were dividing, during its 
period of growth. 
Study of similar bud variations in 
other plants convinced him that the 
same thing was. occurring there. 
ie Be ee bh) |) 
1 Annual report of the Connecticut Agricultural Experiment Station, 1909-10, pp. 134-140. 
176 
