58 POUI^TRY DISEASES AND THEIR TREATMENT. 



of a flock of 1460. Microscopic examination proved that these 

 were dying of tuberculosis. 



Tuberculosis is confined chiefly to adult or nearly adult fowls. 

 Only very rarely, if ever, is it found in growing chicks. Fur- 

 ther it is much more common in fowls than in other kinds of 

 poultry. Two cases in wild geese were reported at the On- 

 tario Agricultural College. Avian tuberculosis is said to be 

 found in turkeys, pheasants, and especially in pigeons. Cage 

 birds are particularly susceptible to this disease. 



Etiology. — Tuberculosis is caused by a minute germ, the 

 Bacillus tuberculosis of birds. These bacteria gain entrance to 

 certain portions of the body and there multiply in vast numbers, 

 causing the formation of small nodules or tubercles. The dis- 

 ease is highly contagious and is spread through the flock by l^e 

 contact of healthy birds with the diseased ones, or with their 

 discharges. 



The relation of avian tuberculosis to that of man and other 

 animals has attracted a great deal of attention. It is a subject 

 of very great importance to the poultryman, not only on accoimt 

 of his flock but also on account of its relation to the health of 

 himself and his family. In this connection, writing some years 

 ago Salmon says : "Many outbreaks (of fowl tuberculosis) have 

 been attributed to infection from eating the sputum of persons 

 affected with consumption. The possibility of such infection is 

 admitted by some authorities and denied by others. It is cer- 

 tain that poultry and pigeons are not easily infected experi- 

 mentally with the tuberculosis of people, cattle and other ani- 

 mals which are classed together as mammals." On the other 

 hand, "The bird or avian tuberculosis spreads rapidly from 

 bird to bird and is easily transmitted experimentally to birds but 

 it has little effect upon most mammals which are very suscep- 

 tible to human tuberculosis. There is, consequently, a marked 

 difference between avian and mammalian tuberculosis. The 

 disease in the two cases does not appear to be absolutely dis- 

 tinct, but should rather be regarded as two varieties of the same 

 malady." 



In the last few years a great deal has been found out about 

 tuberculosis in both birds and mammals. The results have 

 been summarized and extended by Drs. Koch and Rabin£.witsch 

 in an extensive paper dealing with avian tuberculosis and its 



