364 TUBERCULOSIS AS A TYPE OF BACTERIAL DISEASE 



acid-fast bacilli from butter. Brief reference may be made to the 

 organisms discovered by the two last-named workers. 



Binot's Butter Bacillus is in morphological and tinctorial char- 

 acters similar to the tiibercle bacillus. It differs in cultural features. 

 Binot describes it as producing a thick, viscous, creamy layer in 

 broth, from which " stalactites " grow down into the liquid. It grows 

 on gelatine (which it does not liquefy), producing thin creamy irregu- 

 lar surface colonies. On glycerine-agar plates and tubes white colonies 

 appear, becoming straw-coloured, and finally orange. They may 

 attain diameter of two-franc piece or larger; and have a bright 

 glistening surface, and are very adherent to medium. On the surface 

 they soon become wrinkled and irregular, and have scalloped edges. 

 Chromogenic characters are more marked if the growth is exposed to 

 air and light (see Plate). On potato, a scanty growth occurs, which 

 is at first moist, and of a clear yellow colour. On glycerine potato 

 an abundant homogeneous growth occurs, of an opaque yellow colour, 

 turning to orange. Irregular nodosities appear on the colony. The 

 bacillus produces tuberculous-like changes in animals in which it is 

 inoculated. 



2%e Butter Bacillus of Grassberger is very similar to the other 

 members of this group, except that it produces, especially on gelatine, 

 but also on glycerine agar, a dry, much-wrinkled growth not unlike 

 some forms of mould, and of a deep rose colour. There is no liquefac- 

 tion. The wrinkles in the large colonies appear as characteristic 

 markings (see Plate). Milk is coloured throughout by the organism, 

 but not coagulated. There is also a surface growth and deposit, both 

 rose coloured. On potato the growth is similar to tubercle bacillus, 

 but of a deep rose tint. 



{d) Acid-fast Bacilli in Grass, Hay, and Manure. — This second 

 group of acid-fast bacilli associated with milk (marked (d) in the 

 classification above) is often designated as that of the gra^s bacilli. 

 They were first cultured on Timothy grass (Fhleum pratense), which 

 is much valued for feeding cattle.* Since then, however, this grass 

 bacillus has been found in various places, and it or its allies have 

 been isolated from cattle fodder, hay, hay-dust, manure, milk and 

 its derivatives. Morphologically, this bacillus (B. pJilei) is similar to 

 the tubercle bacillus, slender and slightly curved. It contains 

 highly -stained granules and oval, clear spaces ; often grows in threads ; 

 and is branched, and sometimes has clubbed swellings at one end. 

 It is acid-fast in staining, and grows best at incubation temperatures 

 on the ordinary culture media. The colonies become visible in thirty- 



* Oafs tail or Timothy grass (JPhleum pratense). Although well known to the 

 British grower this grass is more extensively cultivated in the United States, where 

 it was introduced from Britain, nearly a century ago, by Mr Timothy Hanson, after 

 whom it is named Timothy grass. 



