in reply, suggests that it is possible that the immature ova are sometimes (e.g. in the cases cited) directly infected by the germ-plasm of the first male, a not improbable explanation, since we know that the spermatozoa do actually reach the ovaries, as is proved by many recorded cases of ovarian and abdominal fœtation. Mr. Spencer scouts his suggestion, and asks—
"Why in such a case each subsequent ovum, as it becomes matured, is not fertilized by the sperm cells present, or their contained germ-plasm, rendering all subsequent fecundations needless?" (p. 68).
Professor Romanes has, however, already by anticipation answered the objection by opining—
"That the life of ids" (i.e. groups of biaphors) "is not commensurate with that of their contained spermatozoa. After the latter have perished and disintegrated, their ids may escape in thousands of millions, bathing in a dormant state the whole surfaces of both ovaries. And if so, it is conceivable that when subsequent ova mature, i.e. come to the surface of their ovaries and rupture their follicles, these dormant ids adhere to their porous walls through which they may pass."
And therefore since the whole of a spermatozoon of a previous sire does not enter the ovum it is not entirely fertilized, and all his traits are not transmitted; but as only part of his spermatozoon enters, the ovum is only partially fertilized, and his traits are only in part transmitted. Mr. Spencer objects "that the surface of a mammalian ovarium is not a spermatheca" (p. 68), but when he speaks of "a foreign germ-plasm permeating the organism," does he not himself seem to consider the tissues in general of the female as a
