578 HORSE, SWINE AND POULTRY DISEASES 



the intestine at such points shows that enormous numbers of tuber- 

 cle bacteria are present. The conclusion that they are liberated 

 through the intestine is unavoidable. The droppings of fowls af- 

 fected with tuberculosis must therefore be regarded as an important 

 factor in the spread of the disease. 



No evidence is at hand to indicate that tuberculosis is spread 

 through the egg. Post-mortem examinations and observations upon 

 living fowls lead to the conclusion that badly infected fowls, at least, 

 do not lay. Considerable attention has been paid to the ailments 

 causing the death of young chicks, but no tuberculosis has been dis- 

 covered among them. The disease would be found in young stock 

 if it were commonly transmitted to the young through the egg. 



The location in which the droppings are deposited bears con- 

 siderable relation to the probability of that material being a means 

 of infecting healthy fowls. The practice of feeding soft food from 

 the ground affords the best of opportunity for the contamination of 

 the food with fresh droppings. Sunlight is rapidly fatal to tu- 

 bercle bacteria, but it by no means has opportunity to freely act upon 

 infectious material out of doors. Indoors, the tubercle bacteria may 

 remain alive and dangerous for many weeks. The eating habits of 

 fowls indicate that they are in danger of infection by way of the 

 crop in the roosting-houses, although no food may be there. Fur- 

 thermore, there always exists the possibility of conveying infectious 

 material by the feet, to the food outside. 



Tests. There is at present no means of detecting the existence 

 of tuberculosis in a fowl until the affection has progressed sufficiently 

 to produce lameness or emaciation. There is reason to believe that 

 fowls may be diseased badly enough to make them a source of dan- 

 ger to other fowls, without suggesting by their appearance that they 

 are affected. The tuberculin test so generally used for the detec- 

 tion of the disease in cattle does not give positive results when ap- 

 plied to tuberculous fowls. Tuberculin is a liquid prepared from 

 beef broth in which the tubercle bacteria have been cultivated for 

 several weeks. When injected under the skin of cattle affected with 

 tuberculosis, it produces a rise of temperature usually about two de- 

 grees above normal. The test, in competent and honest hands, af- 

 fords a ready means for detecting the disease when other means 

 would fail. Trials upon twenty-one fowls affected with the disease 

 have not indicated that the test may be successfully applied to them. 



Even should the tuberculin test prove applicable to fowls, its 

 usefulness would be limited, on account of the impossibility of ap- 

 plying it to a large number of them, as would be necessary on a 

 large poultry ranch. Nevertheless, the test would be very useful in 

 experiments to determine the possibility of the transmission of tu- 

 berculosis of man or cattle to fowls. 



The Control of Tuberculosis in Fowls. There is no known 

 remedy for the cure of tuberculosis in the fowl. Affected birds 

 should be killed as soon as the existence of the disease is recognized. 

 It is useless to attempt treatment. It must be controlled by measures 

 designed to keep the healthy fowls separated from the diseased ones. 



