536 Messrs. Twort and Ingram. Isolating and [Nov. 7, 



We are now conducting experiments with this object. Up till recently 

 we have been unable to obtain any growth of Jbhne's bacillus on the 

 surface of fluid media, and this has been the chief difficulty in preparing 

 an efficient vaccine, but we have now succeeded in inducing it to grow 

 in film formation on glycerine broth containing the timothy-grass bacillus. 

 We consider this a great advance, as the bacillus should now grow more 

 vigorously, as is usually the case with other acid-fast bacilli. 



The specific bacillus of pseudo-tuberculous enteritis, commonly known as 

 Johne's bacillus, is, as already stated, allied to the various tubercle bacilli, 

 and therefore belongs to the same general group. If we accept the 

 classification of micro-organisms adopted by Lehmann and Neunian, it would 

 be more correct to describe it as a mycobacterium, and the scientific 

 name of the micro-organism would then be Mycobacterium enteritidis 

 chronicce pseudotuberculosce bonis Johne, the name by which we suggest it 

 should be known. At the same time, throughout this paper we have 

 thought it better to retain the common name of Johne's bacillus. We 

 were unable to detect any difference in the five strains isolated, and the 

 culture recovered from the experimental bovine No. 4 also agreed in every 

 detail with the other bacilli. In the diseased lesions the bacilli often 

 appear in extremely large numbers. They are present as slender rods, 

 sometimes slightly bent, and are usually between 1 and 2 microns in 

 length. They often show a beaded appearance, but this is not so marked 

 as with the tubercle bacillus. When first cultivated from the animal body 

 on the special media described in this paper, the bacilli grow longer and 

 thicker, and lie side by side in a manner very similar to the tubercle 

 bacillus. If the medium is partially dried they may grow to a length of 

 5 microns or more, and show definite dichotomous branching, with club 

 formation and very distinct beading. When sub-cultured on to moist solid 

 medium, the bacilli soon regain their slender and short form, and in vigorous 

 growing cultures they may become very short and show but little beading. 

 The bacilli at this stage often lie side by side, but loosely and not in the 

 typical manner of the early cultures. Spore formation was not observed in 

 any of our growths. 



In none of the strains have we been able to detect any evidence of 

 motility. 



Like the tubercle bacillus, Johne's bacillus, if obtained from diseased tissues 

 or from a pure culture, stains imperfectly and with difficulty with aqueous 

 solutions of the anilin dyes, but quite well with Gram's method, and better still 

 with Ziehl-Melsen's. It is quite acid-fast, and retains the stain when treated 

 with 25-per-cent. sulphuric acid or 1-per-cent. hydrochloric acid in spirit. 



