AVIAN TUBERCLE BACTERIA 



205 



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

 to be due to extensive lesions in the j 

 viscera. I 



§ 150. The avian tubercle bac- 

 teria. These organisms resemble quite 

 closely those of the human and bovine 

 varieties in their size and general mor- 

 phology as they are found in the tissues 

 of the fowl. A measurement of over two 

 hundred individual organisms in cover 

 glass preparations made directly from 

 organs of fowls gave the following : In 

 the liver the length varied from 1.2 to 

 3.5 /<, in the spleen and in the skin they 

 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. 

 In the preparations from the skin a con- 

 siderable number of them contain polar 

 granules and not infrequently three such 

 bodies were noticed in a single individual. 

 Perhaps the most striking feature con- 

 cerning these organisms in the tissues is 

 their enormousj numbers. Sibley has 

 called attention to the similarity of avian 

 tubercle bacteria to those of leprosy in 

 that they multiply to such enormous 

 numbers without a pronounced breaking 

 down of the tissues. 



This variety is more easily obtained 

 in pure culture from the lesions than the 

 human or bovine forms. Moore obtained 

 pure cultures in about 20 per cent of 



J 



Pig. 46. A glycerine 



agar culture of avian 

 tubercle bacteria. Cul- 

 ture four weeks old. 



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