tent, independent of each other. This becomes clear if 
we invert the argument and ask whether proof of one 
part of the theory proves the other two as well. For ex- 
ample, would the discovery of a wild or fossil form of 
pod corn, although clearly proving pod corn to be the 
ancestral form, either prove or disprove the assumption 
that teosinte is a hybrid of maize and Tripsacum or that 
modern varieties of maize have been modified by intro- 
gression from teosinte? Or would proof that teosinte can 
be artificially produced by hybridizing maize and Trip- 
sacum prove also that pod corn is the ancestral form and 
that modern corn is strongly contaminated with teosinte ? 
Since the three parts of the theory are obviously to a 
large extent independent, it seems appropriate to discuss 
objections to them separately. The remainder of this 
paper is concerned only with the first part: the postulate 
that cultivated corn originated from a form of pod corn. 
The succeeding papers in this series will treat other as- 
pects of the problem. 
Pop Corn, THE ANCESTRAL FORM 
The theory that cultivated maize originated from pod 
corn, a form in which the individual kernels are enclosed 
in floral bracts as they are in other cereals and in the ma- 
jority of grasses, is not original with us, although we 
have made acontribution to it by adding the assumption 
that the ancestral pod corn was necessarily quite different 
from the monstrous pod corn found in modern, highly 
domesticated varieties. The original idea we owe to 
Saint-Hilaire (23), who was apparently the first to offer 
any comment on the origin of cultivated maize and also 
the first to suggest that pod corn represents the ances- 
tral form. We adopted the pod-corn theory only after 
our extensive studies of maize-teosinte hybrids had sug- 
gested to us that teosinte is itself a hybrid of maize and 
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