438 STATE BOARD OF AGRICULTURE. 



branes of eye and mouth are pale. The temperature usually remaius 

 normal (about 10G.5° to 108.5° F.). Occasionally, the bird shows lame- 

 ness as a result of a tuberculous joint or bone. This may be mistaken 

 for rheumatism. At times, there are tuberculous nodules of the skin, 

 especially about the head. The bird may be affected several weeks before 

 any of these symptoms appear. (Fig. 1.) The tissues most frequently 

 affected are the liver, then the spleen, intestines, mesentery and rarely 

 the lungs, kidneys, ovarv\ oviduct and subcutaneous tissue, and at times 

 the joints and bones. The tubercular masses vary greatly in size, rang- 

 ing from mere specks to the size of a large pea, and they may be few 

 in number or thickly sprinkled throughout the organ. (Fig. 2.) TJiey 

 are usually of a yellowish-white appearance and are easily separated 

 from the surrounding tissue. They tend to break down in the center 

 and, if in the intestinal wall or oviduct, may communicate with the 

 passage into which they discharge numerous tubercle bacteria. 



The bacteria are very numerous in the diseased tissue, much more so 

 than in human or bovine tuberculosis. They probably leave the body 

 almost entirely through the alvine discharges and enter with the food 

 almost exclusively. The feeding habits of chickens tend to rapidly 

 spread the disease, and failure to keej) pens constantly clean and dis- 

 infected increases the chances of infection. 



There are a great many affections that may be mistaken by a casual 

 observer for tuberculosis. Especially is this true of diseases of the liver 

 or nodules in other organs. The liver disease may be due to fatty de- 

 posits, coccidia or other protozoa, as in black head, pus-producing bac- 

 teria, fungi, or tumors of a malignant nature as cancer. A careful 

 microscopic examination is necessary to determine the exact nature of 

 any of these conditions. With any disease, it is important to find out 

 early the exact nature of the trouble. Au}^ suspicious cases should be 

 sent to this laboratory for diagnosis. 



There is positively no known treatment of any value for tuberculosis 

 of chickens. When a positive diag-nosis has been made, the best solution 

 of the problem seems to be to kill the whole flock and use those not 

 affected for food, burning the diseased ones. After this, a careful dis- 

 infection of the chicken house and yards is necessary before it is safe io 

 introduce new birds. As a preventive, may be recommended the exclu- 

 sion of the disease by raising stock from eggs known to have come from 

 health}^ birds, and refusal to buy stoek from poultrymen that cannot 

 offer evidence of flocks free from tuberculosis. Expert advice covering 

 each individual case should be secured since circumstances might alter 

 the procedure greatly. With those finding the disease, this laboratory 

 will gladly cooperate in its eradication. In this way, it may be possible 

 to adapt the methods employed to the exigencies of the case. 



BACTERIOLOGICAL LABORATORY. 



