150 



BIOLOGIC BASIS OF SEX 



Fig. 2.36. Composite drawing illustrating the condition of the genital systems in a group 

 of "gynandromorphic" mice, which have an ovary on one side of the body and a testis on 

 the other, after Hollander, Gowen and Stadler (1956). On the side of the testis (which as a 

 rule was partially or entirely descended and is shown as dissected out) a complete male duct 

 system with seminal vesicle is present; the female genital tract is absent on this side. On the 

 side of the ovary a complete female genital tract is found, although it varied greatly in size 

 in different cases. On this side the male duct system was usually absent, but appeared in 

 whole or in part in about one third of all cases. Compare with conditions induced by a uni- 

 lateral testis graft shown in Figure 2.35. Abbreviations: Bl., bladder; Ep., epididymis; O, 

 ovar}^; Ovd., oviduct; R, rectum; S.V., seminal vesicle; T, testis; U, uterus; V.D., vas 

 deferens. 



bears on this point. When the pituitary is 

 absent the normal secretory activity of the 

 embryonic testis may be materially reduced. 

 In male rabbit fetuses deprived of their 

 hyi)ophyses by decapitation, although the 

 testes are present, an apparent decrease in 

 endocrine activity has local effects which 

 reseml)le those of castration (Jost, 1951a, 

 1953). In their lowered state of activity, the 

 influence of the testes on the accessory sex 

 structures is graduated according to dis- 

 tance. Structures near the gonads, such as 

 the vas deferens and epididymis, are nor- 

 mally developed but the more distant sinus 

 derivatives and external genitalia are of fe- 

 male (i.e., castrate) type. Here again a level 

 of activity adequate to maintain normal 

 development of nearby structures is ineffec- 

 tive at greater distances, and the result is 

 not compatible with the view that the hor- 

 mone is distributed only thi'ough the blood 

 stream. 



Approaching the ciuestion from yet an- 

 other direction, a clear demonstration of 

 local action by a hormone appears in an ex- 

 periment cited previously, in which an em- 

 bryonic testis is engrafted between the lob- 

 ules of the seminal vesicle of a castrate 

 host; there is complete cytologic recovery 

 of the atrophic epithelium in lobules con- 

 tiguous with the graft, but the effect di- 

 minishes rapidly with distance and soon dis- 

 appears. Greenwood and Blyth (1935) have 

 also described a sharply circumscribed ef- 

 fect on the feathers of capons. A very small 

 dose of female hormone injected subcutane- 

 ously changes the pigmentation of growing 

 feathers at the site of injection, but beyond 

 a very short distance it has no effect. On the 

 other hand, after local implantation of hor- 

 mone pellets, both localized and more dis- 

 tant effects may be registered at the same 

 time, indicating that both modes of distri- 

 bution are simultaneously effective [cf. 



