List of Illustrations. 



Fig. Page 



1. Section through the penis of a eunuch 28 years old . 6 



2. Section through the middle of the penis of a normal adult 7 



3. ScoPEC of 28, castrated at the age of 16 . . . 8 



4. Man of Central Europe with well developed body hair 9 



5. scopec of 24, castrated at the age of 5 . . . lo 



6. Adult European woman . . . . . . . ii 



7. Normal male rat, i month old . . . . . 19 



8. Normal adult male rat . . . . . . . 19 



9. Male rat, 8 months old, castrated at the age of i month . 20 



10. The penis and intromittent sac of guinea pig, castrated 



at different ages . . . . . . . 21 



11. Penis of guinea pig castrated at the age of 4|r months, 



DRAWN 2 months LATER ...... 22 



12. Seminal vesicles of a normal guinea pig i^ years old . 22 



13. Seminal vesicles of a guinea pig 21 months old castrated 



AT the age of 2 WEEKS ...... 23 



14. Seminal vesicles of guinea pig castrated at the age of 



4^ months, drawn ii months later .... 23 



15. Influence of castration on the rabbit's penis . . 24 



16. Influence of prepuberal castration on the uterus of 



RABBIT ......... 25 



17A, B, c. Histological features of the uterus of normal 



AND castrated RABBITS ...... 26, 27 



18. Profile of normal and castrated cows ... 29 



19. Pelvis of a new-born male lamb ..... 30 



20. Pelvis of a new-born female lamb ..... 30 



21. Pelvis of an adult ram ....... 30 



22. Pelvis of an adult sheep . . . . . . 31 



23. Pelvis of a ram castrated at an early age . . . 31 



24. Pelvis of a sheep castrated at an early age . . 31 



25. Growth of comb and spurs in the normal and in the 



castrated cock ........ 37 



26. Comb of normal and castrated animals in Brown Leghorn 38 



27. A Brown Leghorn capon, 3 years old .... 39 



28. Head apparel in the cock castrated when one year old . 41 



29. Ovariotomized Pullet ....... 42 



30. Hen castrated four months previously .... 43 



31. Normal Rouen duck 



32. Normal Rouen drake 



33. An ovariotomized duck 

 34A. Normal Sebright cock 

 34B. Castrated Sebright cock 



35. Pad of male Rana temporaria in July, 



36. Pad of male Rana temporaria in April, at time of heat . 53 

 37-45. Transformation of Inachus by Sacculina ... 60 

 46. Male rat, 8 months old, with testicular autotransplanta- 



tion at an age of i month ..... 83 



XV 



44 

 45 

 45 



. 48 



49 



AFTER PERIOD OF HEAT 52 



