DESCRIPTION OF JOHNE'S BACILLUS 63 



When first cultivated from the animal body on any 

 of the special media (media containing the dead bodies 

 of other acid-fast bacilli), the bacilli may grow longer 

 and thicker, and lie side by side in a manner very 

 similar to the tubercle bacillus. This is especially so 

 if the medium is a little dry or old, or for some reason 

 is not particularly good. On such media they ma}^ 

 attain a length of 4 /x or more, and may show 

 definite dichotomous branching, with club formation, 

 and very distinct beading. When subcultured on to 

 moist and good media, the bacilli soon regain their 

 slender and short form, and in vigorous growing 

 cultures, especially if fluid media is used, they may 

 show little or no beading, and may become very short, 

 appearing almost like cocci. 



M'Fadyean, Sheather, and Edwards have noticed 

 "numerous bacilli of quite exceptional length" in 

 smears made from a piece of rectal mucous membrane 

 taken from an animal intra vitam. The dimensions ot 

 these bacilli are not given, but they are stated to have 

 been much above the average length of Johne's bacillus, 

 and arranged in bundles, in which all the bacilli were 

 approximately parallel. Cultures were made from the 

 tissue on to ^g^ medium containing dead tubercle 

 bacilli, when the bacilli grew ; but on ordinary Dorset's 

 ^gg medium no growth took place. These authors have 

 not observed any definite branching of the bacilli. 



Spore formation has not been present in any of our 

 strains, and in none of our cultures have we been able 

 to detect any evidence of motility. In these respects 

 Johne's bacillus agrees with the other members of the 

 acid-fast group. 



Holth states that in morphology and staining 

 characters his strain of Johne's bacillus agrees with 

 the description given in our original paper. 



