THE URO-GENITAL SYSTEM 123 



These centers contain pus which may be caseous, and 

 the various centers communicate by means of fistulous 

 tracts. 



Treatment consists of ablation of the entire mass, 

 which is ordinarily not difficult as the lesion is sub- 

 cutaneous and is definitely circumscribed. 



Actinomycosis 



Actinomycosis may affect the scrotum of castrated 

 swine, but is not common. 



Parasites 



Infestation of the castration wounds with screw- 

 worms (larvae of the Campsomyia macellaria) are very 

 common in the southern part of the United States. 

 These larvae, burrow into the tissues, thus mechanically 

 injuring them and providing an avenue of entrance for 

 various bacteria. 



Lesions. The principal lesions consist of an active, 

 acute inflammation with or without the production of 

 pus. The surrounding tissues are tumefied, hyperemic, 

 hemorrhagic, and contain the larvae. The extensive 

 tumefaction developing within one or two days after 

 castration is the most evident symptom. On a close 

 inspection, larvae may be observed near or upon the 

 surface, and by manipulation of the lesion larvae may 

 be forced out upon the surface. In cases of screw- worm 

 infestation there is a constant sero-sanguinous discharge 

 that by attracting the female fly favors repeated rein- 

 festation. 



Treatment. All that can be done in cases of screw- 

 worm infestation is to support the strength and minister 

 to the comfort of the animal and prevent a further 

 infestation from the deposition of more eggs or larvae 

 upon the wound and patiently wait for the investing 

 larvae to reach the stage of development when they 

 voluntarily leave the wound to pupate in the ground. 

 This occurs in three to five days. 



The application of chloroform, naphthalene or other 

 chemicals to the wound is worse than useless. .Such 



