786 The Theory of Sex and Sexual Genesis. (August, : 
male or female, and thus no attempt being made to tell from the 
size which were moneecious. Then by opening the spathe the 
inference was found to be either right or wrong, or partly right 
and partly wrong, and was so recorded. Of the 213 plants 
seventy-four were judged, from their size, to be females, which 
proved on examination to be such, and ninty-six were judged to 
be males, which proved to be such; seven were judged to be 
females and ten to be males, which proved to be moncecious; 
thirteen, mostly of medium size, were judged to be females which 
proved to be males; and thirteen, mostly of medium size, were 
judged to be males which proved to be females. Of the 137 
plants fifty-seven were rightly judged to be males, and sixty-four 
rightly judged to be females; so that there were only sixteen out 
of the whole number whose sex was wrongly inferred from the 
size. Thus in the great majority of cases the sex was correctly 
inferred from the size of the plants; and in nearly all the cae 
where the inference was wrong the plants were of medium siz 
in which case there would necessarily be much uncertainty M 
attempting to determine the sex in this way. ; 
Here we have, I think, very conclusive evidence that the female 
sex is determined by a relative predominance of the conditions 
of nutrition or cell-growth over the conditions of differentiation 
or cell-division, as compared with the correlation of these condi- 
tions in the production of the male sex. All the external om 
tions of development, comprising temperature, the supply 
oxygen and carbon dioxide in. the air, and the supply @ EEEE 
A he 
and other matters in the soil, are precisely the same for zie : 
plants of each group. The only difference is, that g pea 
corms contain a greater quantity than the smaller ones 
rated and stored-up proximate compounds to be organiżed aro 
a single axis of growth. And from the larger aggregatio! fe 
nutritive matter female plants are developed; while from | 
smaller aggregations male plants are developed. : most : 
The observations or experiments of Knight furnish eee ) 
conclusive evidence we have of the nature of the ae “that 
tions which act to determine the sex in plants. Hate solely 
several kinds of moncecious plants can be made to pe light 
male or solely female flowers, by regulating the quani te er 
and heat under which they are grown. If the heat be F iv 
compared with the quantity of light which the pant 
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