PLATE CULTURES. 493 



splintery (see Plate 59, i) and of a yellowish color. Mag- 

 nified 1000 times : Stained in segments, highly polymor- 

 phous, short, long, thick, thin, clubbed, pointed, also 

 with the form of cocci (apparently diphtheria or pseudo- 

 diphtheria or xerosis bacilli). In the pseudodiphtheria 

 bacillus the border is often coarsely granular, similar to 

 sarcinas. The further examination is conducted according 

 to page 384. 



4. Larger, moist, sometimes slimy, luxuriant colonies, 

 somewhat elevated, whitish to gray, with transmitted 

 light somewhat iridescent. When magnified sixty times, 

 the edge is smooth. Microscopic preparation magnified 

 1000 times: Small, plump or more slender rods, perhaps 

 also isolated short chains. Not stained by Gram's method. 

 Belongs to the group of non-sporulating bacteria. Perhaps 

 or probably the Bact. coli or a closely related variety. It 

 is to be further studied regarding motility, gas-formation, 

 indol, coagulation of milk, according to page 169, etc. 

 When transferred to gelatin plates, the colon group pre- 

 sents, upon slight magnification, the characteristic, wavy, 

 smooth-edged, transparent colonies with intersecting lines. 



5. Macroscopic : Similar to the colonies described under 

 4, but never slimy; grayish-white, often gray. When 

 magnified sixty times, the border is matted or curly. 

 Microscopic preparations magnified 1000 times show 

 sturdy bacilli, of equal length, the ends not rounded, 

 staining by Gram's method, often united in chains (very 

 probably sporulating organisms of the subtilis, anthrax, 

 and mesentericus group). To be further studied accord- 

 ing to page 304. 



6. Essentially the same as under 5, but the periphery 

 is exceedingly delicate and transparent. There is neither 

 observed formation of curls nor irregular breaking up of 

 the periphery into a felty structure. The microscopic 

 preparation magnified 1000 times shows bacilli similar to 

 those described under 5, but usually arranged in pairs 

 (probably Bacterium duplex). 



It may here be again stated for the beginner that the 

 diagnosis, especially the separation of the bacteria into 

 separate groups, may be much facilitated by paying atten- 

 tion to" the periphery of the colonies. In the follow- 



