CONSTITUTIONAL DISEASES 121 



pearly, grayish-white nodules varying in size from 

 a pin-head to a pea, or even larger. In these 

 larger nodules there will be noted a cheesy mass 

 which, as the lesions become older, they become 

 impregnated with calcium (lime) and then cut 

 like gritty material. In healed tubercles there 

 may be a solid calcareous (stony) mass. Usually 

 the diseased organs are enlarged. Fig. 42 illus- 

 trates a liver and spleen studded with pearly 

 tubercles of pin-head size. This liver was from 

 a hen afflicted with tuberculosis. 



Upon opening the intestine of a tuberculous 

 bird there may be noted ulcers, usually small in 

 size, and a thickening of the wall. The abdom- 

 inal lymph glands (kernels) are tuberculous. At 

 times these show small tubercles from the size 

 of a pin-head to larger, at other times a cheesy 

 mass (caseation necrosis), and in still older areas 

 an infiltration with lime salts. Small tubercles 

 may also be found in the lungs and other adja- 

 cent tissue. 



Like in the higher animals, the bones become 

 tuberculous, there is noted swelling tubercles and 

 caseation ; later calcification. 



Treatment. — Treatment of the affected bird is 

 not to be thought of. As shown above, the germs 

 of the disease are so often spread through the 

 droppings that the only sure means of eradicat- 

 ing the disease from a flock is to kill all the birds 

 in the flock and if possible move the henhouse to 

 a new location and have new runs. If this is not 

 practicable, thoroughly disinfect with five per cent 

 carbolic acid or five per cent creolin, all fences, 

 feed troughs, watering tanks and buildings, as 

 indicated under cholera. 



Birds from an infected flock should not be sold 



