APPENDIX 133 



SPECIFIC DISEASES FOR WHICH ANIMAL INOCULATIONS ARE MOST 

 COMMONLY RESORTED TO FOR DIAGNOSTIC PURPOSES 



Tuberculosis. — Guinea pigs are preferable, although rabbits may 

 be used. With tuberculous tissues either of two methods may be 

 employed, (i) A small piece (about the size of a pea or bean) of 

 the tissue may be inserted under the skin by first making an incision 

 with a sharp scalpel through the skin and superficial fascia and then 

 with a pair of fine forceps insert the bit of tissue well under the skin 

 and close the opening with one or more sutures. (2) The tissue 

 may be crushed in a mortar and thoroughly mixed with a few cubic 

 centimetres of sterile water or bouillon and then injected with a 

 hypodermic syringe. The needle should be of large cahbre. If it 

 is suspected milk, it may be injected into the abdominal cavity. If 

 the material is tuberculous and contains living tubercle bacteria, the 

 death of the animal follows in from three weeks to four months. 

 Usually the lymphatic glands of the groin and axilla are enlarged 

 and often caseous. If. a guinea pig is used, the liver, spleen, lungs, 

 and kidneys are liable, in the order named, to be affected ; if a rabbit, 

 the lungs are often the first of the visceral organs to be attacked. 

 (See pathology for description of tissue changes.) 



Glanders. — Male guinea pigs should be used. The material usu- 

 ally consists of the nasal discharge from the .suspected glandered 

 horse, or bits of scrapings from the ulcers, or pieces of affected 

 tissue. The method to be followed is precisely the same as with 

 the subcutaneous injection of tuberculous material. In these cases 

 there is liable to be a local swelling and abscess. The first indica- 

 tion of glanders noticed is usually orchitis. The lymphatic glands 

 in the groin are also enlarged. After the orchitis becomes well 

 marked the guinea pig may be chloroformed and examined. Pure 

 cultures of the specific organism can be obtained in most cases from 

 the suppurating focus in the testicle. The spleen is usually en- 

 larged and sprinkled with grayish nodules. Other organs may be 

 involved. 



Rabies. — The method usually followed in diagnosing rabies is to 

 inoculate a rabbit, guinea pig, or dog beneath the dura with a bit 

 of the brain or spinal cord of the suspected rabid animal. Other 

 methods are being introduced and the guinea pig is reported by 

 some to respond more promptly, but in ray experience the subdural 



