24 ORIGIN OF SEX. 
In the case of Norway spruces it is “only in the fourth or 
fifth year, when vitality in the spur is nearly exhausted, do male 
flowers abundantly appear.” 
Mr. David Moore, in his morphology of Nepenthes,* says that 
“vigor and healthiness increase the female line of vital force in 
vegetables, while weakness is more conducive to the male devel- 
opment.” When growth has ceased, maturity and complete de- 
velopment are accomplished, and the business of reproduction 
exclusively occupies the plant. 
From all this it appears then, that while the plant is mostly oc- 
cupied in vigorous growth, while it is yet succulent, immature, or / 
is, in other words, undeveloped, does it bear the largest proportion — 
or principally female flowers. As growth is antagonistic to de- 
velopment, and it is only after perfect development is reached 
that the reproductive function is most active, we are forced to con- 
clude that the production of male flowers or fruit is a higher effort i 
of the plant than the production of females. $ 
I have ventured to enunciate it as a law} deduced from a thor- 
ough study of the subject, that the greater the fecundity, in sin- 
gle births, the larger the proportion of male children, and vice — 
versa. I have also said that the begetting of males is a higher — 
role in the reproductive act of the mother than the hegetting of | 
females ; while the begetting of females on the part of the father — 
is a higher reproductive role than the begetting of males.{ In this — 
article it has been shown that the greater the “vigor” (rapidity of 
growth and excessive vital and vegetative action) the larger the 
proportion of females produced. Now, it is so well known and 
so universally recognized and pointed out by physiologists, that _ 
this same vigor is directly antagonistic to reproduction, that it is 
scarcely necessary for me to mention it. Hence females are be- 
gotten when the system is more occupied by the process of growth, 
reparation or disease, than when males are begotten. 
Dr. Henry Hartshorne§ has maintained Mr. Meehan’s view of 
the relation of vigor to sex. To the facts stated I fully agree, 
* Trans. of the Royal Irish Acad., Vol. xxiv, p. 629, 1870. 
t The Relative Viability of the Sexes, etc. N. Y. Medical Record, June 16, and July 
15, 1873, p. 301; and Statistics of Philadelphia, Proc. Socjal Sci. Assoc., 1873, p. 18. 
. ł See farther, in the author’s thesis, already alluded to, in foot-note; also his paper — 
on Laws of Transmission, ete., ete, 
e Relation between Vi: 
§On the 
a ony 
Proc. Amer. Assoc. Ady. Sci., 1872, PP 
