214 TUBERCULOSIS 



counter-stain is desired Gabbett's decolorizing and counter-staining 

 solution is very convenient. 



gabbett's solution 



Methylene blue (powder) 2 grams 



10% sulphuric acid 100 cc. 



After staining with the carbol fuchsin treat the preparations with 

 this mixture until the film has a faintly bluish tint. This solution 

 decolorizes and counter-stains at the same time. Care must be taken 

 not to confuse the other acid fast bacteria with those of tuberculosis. 

 The acid fast bacteria other than tubercle, are decolorized with acidulated 

 alcohol (3 per cent hydrochloric acid in 95 per cent alcohol). 



§ 154. Animal inoculation for purposes of diagnosis. 

 Guinea pigs are preferable, although rabbits may be used. 

 With tuberculous tissue either of the two methods described 

 below may be employed. 



1. 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 ti.ssue may be crushed in a mortar and thor- 

 oughly mixed with a few cubic centimeters of sterile water or 

 bouillon and then injected with a hypodermic syringe. The 

 needle should be of large calibre. If it is suspected milk, it 

 may be injected into the abdominal cavnty. 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 in the gioin and axilla are en- 

 larged and often caseous. If a guinea pig is u.sed, the liver, 

 spleen, lungs and kidneys are liable to be affected, in the 

 order named ; if a rabbit, the lungs are often the first of the 

 viscera to be attacked. 



In avian tuberculosis it is necessary to use chickens 

 instead of guinea pigs. The}^ may be inoculated subcutane- 

 ously or into the abdominal cavity. Several weeks may be 

 necessary for the disease to develop sufficiently to distinguish 



