312 A MANUAL OF BACTERIOLOGY 



Tuberculosis in animals. The majority of the domestic 

 animals are subject to tuberculosis. It is most common 

 in the ox, pig, and horse, much less so in the sheep and 

 goat, cat and dog. Wild animals, both mammals and 

 birds, in a state of captivity are also specially prone to be 

 attacked, and a large number of the deaths in Zoological 

 Gardens, particularly among the apes, are due to this 

 disease. 



In the ox the tuberculous lesions are most frequently 

 met with in the lymphatic glands and serous membranes, 

 particularly the pleura, and in the lungs and liver, while 

 the fat and muscular tissues, which constitute the major 

 part of " meat," are very rarely affected. On the pleura 

 the growths take the form of nodular masses, which from 

 their arrangement are popularly termed " grapes " or 

 " angle berries." 



In carp, tubercle-like nodules are occasionally met with 

 in which a bacillus resembling the tubercle bacillus in 

 morphology and staining reactions is present. It grows, 

 however, much more freely than the true tubercle bacillus, 

 and though inoculable into fish and frogs, is non-inoculable 

 into warm-blooded animals. But it yields a tuberculin 

 which reacts with mammalian tuberculosis, and by feeding 

 carp on the mammalian tubercle bacillus this can apparently 

 be transformed into the piscian variety. 1 



Bird or avian tuberculosis undoubtedly differs in many 

 respects from mammalian tuberculosis. The tuberculous 

 new formations may be very large, but do not show nearly 

 such a disposition to caseation or suppuration as the 

 human lesions. Epithelioid cells form the major part of 

 the growth, and giant-cells are very infrequent. One 

 remarkable feature is the enormous numbers of bacilli 

 which may be present in the tissues ; in places they may 

 be so numerous and closely packed as to form distinct 



1 See Himmelberger, Centr. f. Bakt., Abt. I (Orig.), vol. 73, p. 1. 



