1884, ] 
segment of the sexual apparatus, of both the corresponding male 
and female organs. We can only refer all such instances to the 
laws which regulate the occasional production of local duplicities 
in different other organs of single bodies, and at the same time 
confess our present ignorance of what these laws are. We know 
that various individual muscles, nerves, &c , are not unfrequently 
_ found double, and that in the internal organs of the body exam- 
_ ples of duplicity in individual viscera are occasionally, though 
rarely observed in the heart, tongue, trachea, césophagus, intestinal 
canal, &c. In the several organs composing the reproductive 
_ apparatus, instances of similar duplicity would seem to be more 
common than among any other viscera.” That they should thus 
be more common is what theory would indicate without assuming 
that they constitute a recurrence to an ancestral hermaphrodite 
The Theory of Sex and Sexual Genesis. 779 
According to Darwin the sterility of hybrids is due mainly to 
an imperfect development of their reproductive organs. That 
there should be a greater derangement of the reproductive appa- 
ratus than of other parts, in an organism which is the product of 
à cross between two species, is what the theory of sex here pro- 
posed would indicate. For in the reproductive organs two redun- 
dant types have to be blended; and when a cross is effected be- 
a tween individuals of distinct species these two types represent 
Parts that are functionally distributed among four distinct forms. 
2. General principles pertaining to the formative conditions in 
; embryo also suffice to explain why it is that from a common 
onic type for the species each individual normally under- 
; 898s so pronounced a one-sided development, to ultimate in the 
a characters of one or the other of the differentiated sexes, 
Peat of developing equally and imperfectly the characters or 
een of both. In considering this question these two facts 
ould be borne in mind: 1. That where the same portion of 
: Primary tissue develops into one sexual organ in one of the 
AS aig into a different organ in the other sex, it is impossible 
TRN Organs to be developed in the same individual. 2. That 
a Patts of the body of the forming embryo upon which the 
-their | organs are immediately dependent for the conditions of 
the as luti on, considered as a nourishing apparatus, have not 
‘ 7 Pacity for supplying the conditions requisite to the full 
— of all the organs of both sexes, even if they were 
| of all Co€xisting in a fully developed state. 
