CONSTITUTIONAL DISEAS.ES 145 



thirty-five per cent. The white blood cells are slightly in- 

 creased in numbers. 



Diagnosis. — Many investigators claim that l)irds will not 

 react to subcutaneous injections of tuberculin or to tuberculin 

 dropped into the eye of a tuberculous bird. VanEs and 

 Schalk have shown that tuberculin (50 per cent) made from 

 the avian type tubercle bacilli, injected rather superficially 

 in the comb or wattles (intradermal method) wdll produce 

 a swelling as in similar tests in mammals. Only about one 

 drop is injected. In a test of 600 birds it was found that the 

 intradermal test was accurate in 97.77 per cent. 



Post Mortem Findings. — Owing to the fact that most birds 

 are infected with tul^ereulosis through contaminated food, 

 we find most of the lesions in the abdominal organs. Of 

 these the liver is the most often diseased. Next in frequency 

 may be named the spleen, peritoneum or lining of the ab- 

 dominal cavity, ovaries, gizzard, intestines, lungs, kidneys and 

 bones. 



As indicated above, the areas may appear as pearly, grey- 

 ish-white nodules varying in size from a pm-head to a pea, 

 or even larger. In these larger nodules there wdll be noted 

 a cheesy mass which, as the lesions become older, becomes 

 impregnated wdth calcium (lime) and then cuts like gritty 

 material. Lime deposits in tuberculous lesions of birds are not 

 so abundant as in tuberculosis of mammalia. In healed 

 tubercles there may be a solid calcareous (stony) mass. 

 Usually the diseased organs are enlarged. 



Upon opening the intestines of a tuberculous bird there 

 may be noted ulcers, usually small in size, and a thickening 

 of the wall. The abdominal lymph glands are tuberculous. 

 At times these show small tubercles from the size of a pin- 

 head to larger, at other times a cheesy mass (caseation ne- 

 crosis), and in still older areas an infiltration with lime salts. 

 Small tubercles may also be found in the lungs and other 

 adjacent tissue. 



Like in the higher animals, the bones become tuberculous, 

 there is noted swelling, tubercles and caseation ; later calcifi- 

 cation. ' ! 



Treatment. — Treatment of the affected bird is not to be 

 thought of. As shown above, the germs of the disease are 

 so often spread througli the droppings that the only sure 

 means of eradicating tlie disease from a flock is to kill all the 

 birds in the flock and if Tjossible move the henhouse to a new 

 location and have new runs. If this is not practicable, thor- 

 oughly disinfect with five per cent carbolic acid or five per 



