AVIAN TriJERCLE I5ACTEKIA 205 



It is due to joint lesions in some cases. In others it appears 



to be due to extensive lesions in the 



viscera. 



i^ 150. The avian tubercle bac- ' 

 teria. These organisms resemble quite /""X 



closelj' those of the human and bovine / \ 



varieties in their size and general mor- \. 



pholog\' as they are found in the tissues "J^- 



of the fowl. A measurement of over two f* 



hundred individual organisms in cover 

 glass preparations made directly from ^ c / 



organs of fowls gave the following : In ' ,-^-^.t. - 

 the liver the length varied from 1.2 to '''^. " — ^ J 



3.5 /<, in the spleen and in the skin they '^ f^ijP'i'^- 



varied from i to 4 // in length. A gen- 

 eral average gave a length of 2.7 //. They 

 often appear in these preparations in ' ' , ' ^ 



dense masses. Chains made up of a ^ 



number of short elements are rarely pres- • 

 ent. Granules are occasionally observed. V-. o ' 



In the preparations from the skin a con- 

 siderable number of them contain polar 

 granules and not infrequently three such 

 bodies w^ere noticed in a single individtial. 

 Perhaps the most striking feature con- 

 cerning these organisms in the tissues is 

 their enofmousj numbers. Sibley has 

 called attention to the similarity of avian 

 tubercle bacteria [to those of leprosy in 

 that the}' multiply to such enormous 1\ ^ 



numbers without a pronounced breaking 

 down of the tissues. 



This variety is more easily obtained -•« wtb *»- 



in pure culture from the lesions than the ^'^''- '^^- '"^ sh'rrhtt: 



. , • , agar culture oj avian 



human or bovine forms. Mooreobtained ^„^^.,.^./^. ^,,,^.-;-/«. Cul- 



pure cultures in about 20 per cent of lure four :c-:-k<; oi.i. 







A 



