314 HEALTH, DISEASE AND ENEMIES 



Infectious Diseases. — There are two diseases which it is 

 well to mention since they are very highly contagious and 

 if they attack a flock of poultry they will carry off many 

 birds, and cause the total failure of the enterprise. These 

 diseases are tuberculosis and fowl cholera. Tuberculosis 

 is caused by the bacillus tuberculosis, the same organism 

 which produces the disease in cattle and other animals. 

 The disease affects the lungs, liver, and intestines. Birds 

 are especially prone to tuberculosis, if large flocks are crowded 

 into stuffy quarters. Fresh air and sunlight are the best 



Fig. 172. — When a male bird's comb is severely frozen the points will usually 

 be killed and will later drop off. The points marked A. are those which are frequently 

 lost by freezing. 



preventives. The disease causes rapid loss of flesh, and 

 all birds whose breasts look thin and emaciated should be 

 examined after death for sore spots on the lungs, white 

 spots on the liver and small nodules on the outside of the 

 liver. If any of these symptoms are found, it is absolutely 

 certain that the bird is suffering foom tuberculosis, and all 

 birds affected should be culled out, killed, and their carcasses 

 burned. It is probably wise to sacrifice the entire flock 

 and start again. Before beginning again, the entire area 

 where the birds have run should be thoroughly disinfected, 

 and any faults in the construction of the houses corrected. 



