112 



ESSENTIALS OF BACTERIOLOGY 



Bouillon. Bouillon containing 4 per cent, glycerin is a very 

 good nurture ground. 



Varieties. Branching and other aberrant forms are not rare, 

 and the tendency now is to class the organism with the "higher 

 bacteria." Other acid-fast bacilli exhibit similar types, and it is 

 possible that the bacillary parasitic form is only one stage in 

 the life-history of the organism. 



Little granules, arranged like streptococci, which take the 

 characteristic stain, and look as if the protoplasm had been 



'-~ </ > -*\ \ 



<& /^A.t.ti ^ 



J^.< ,/4 ./ ^j// x v*K> 



i^'^^'i^^N* 



i jK / >* -* *m * 4* J*? i 



>j^<; 



*^ / 



Fig. 59. Tubercle bacillus in sputum (Frankel and Pfeiffer). 



destroyed that inclosed them, are frequently found in sputum. 



Bovine tubercle bacilli are about one-third smaller than human 

 tubercle bacilli. 



Staining. The tubercle bacilli require special methods to 

 stain them, and a great number have been introduced. They 

 are stained with great difficulty: but once stained, they are 

 very resistant to decolorizing agents. Upon these facts all the 

 methods are founded. 



It will be necessary to describe only those methods principally 

 in use; and as the examination of sputum for bacilli is of so 



