USE OF ANIMALS Ig9 



SPECIFIC DISEASES FOR WHICH ANIMAL INOCULATIONS ARE MOST 

 COMMONLY RESORTED TO FOR DIAGNOSTIC PURPOSES. 



Tuberculosis. Guinea pigs are preferable, although rab- 

 bits may be used in cases of bovine tuberculosis. "With tu- 

 berculous tissues either one of two methods may be employed. 

 (1) A small piece (about the size of a pea or bean) of the tis- 

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

 Avith a sharp scalpel through the skin and superficial fascia 

 and then with a pair of fine forceps inserting the bit of tissue 

 well under the skin and closing the opening with one or more 

 sutures. (2) The tissue may be crushed in a mortar and 

 thoroughly ground with a few cubic centimeters of sterile 

 water or bouillon and then injected with a hypodermic 

 syringe. Suspected milk may be injected directly into the 

 abdominal cavity. If the material contained living tubercle, 

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

 months. Usually the lymphatic glands of the groin and axilla 

 are enlarged if the inoculation was subcutaneous. 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. Rabbits 

 should not be used if the material to be inoculated is of 

 human origin. 



Glanders. Male guinea pigs should be used. The ma- 

 terial usually consists of the nasal discharge from the sus- 

 pected glandered horse, 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 tu- 

 berculous material. In these cases there is liable to be a* local 

 swelling and abscess. The first indication 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 cul- 

 tures of the specific organism can be obtained in most cases 

 from the suppurating focus in the testicle. The spleen is 



