CASTRATION — ANATOMY. 179 



are less liable to stray, and bitches cease to attract strange dogs. 

 Finally, certain diseases of the generative organs are sometimes 

 cured by operation. Thus in man castration has been employed 

 for the reduction of enlarged prostate, and in the dog operation for 

 the same object was suggested by Dr. Clarke (see " Veterinarian," 

 1 895) . The pathological enlargement of the gland gradually diminishes. 

 In man osteomalacia is said to have been beneficially affected by 

 castration, but how far the procedure is likely to succeed in animals 

 remains to be proved. On the other hand, " spaying " in cows 

 often removes nymphomania ; and unilateral oophorectomy, removing 

 the cystic ovary, has been successful in sterility. Castration is also 

 indicated by the presence of malignant tumours and fistulse, in certain 

 injuries of the testicles, and in scrotal hernia. 



Castration seems to have been performed on animals since the 

 earliest times, and is still an exceedingly common operation. Owing 

 to the essentially different methods of procedure in male and female 

 animals, castration will be treated of separately in each sex. 



Castration of Male Animals. Experience shows that male animals 

 are best castrated young. Many of the advantages claimed for 

 operation, such as the change in bodily form, are lost when it is too 

 long deferred. 



Excluding the first few weeks of life, most domesticated animals 

 undergo operation during the first year. The horse is an exception, 

 because in it the testicles lie within the inguinal canal during part 

 of the first year, towards the end of which they usually descend into 

 the scrotum, and so become readily accessible. Moreover, horses 

 castrated during the first year often assume a female type, whilst 

 those in which operation is deferred develop to a greater extent. 



Anatomy. The testicles are suspended in the scrotum by means of the 

 testicular cords. The scrotum and the structures it encloses may be 

 divided from without inwards into the following layers : 



1 . The outer skin. This is soft and thin, usually hairless, and in the horse 

 black and shining ; it is very extensible, and is directly continuous with 

 the common integument. In ruminants the scrotum shows a distinct 

 neck ; the skin covering it is light coloured, and exhibits little hair. In 

 swine the scrotum, which is broad and smooth, lies between the hind 

 quarters, close under the anus ; in carnivora it is somewhat lower. 



2. Beneath and intimately connected with the skin is the tunica dartos, 

 which consists of a modified subcutis abundantly supplied with unstriated 

 muscular fibres, elastic and white fibrous tissue. Above it is connected 

 with the yellow elastic abdominal tunic, while a mesial prolongation, the 

 septum scroti, serves to divide the scrotum into two equal pouches. 

 Strictly speaking, the skin and tunica dartos together form the 

 scrotum. 



