i^o Journal of Agricultural Research voi. xix. N0.4 



to 6 weeks. In old isolations curd usually is absent. The medium does 

 not become viscid or slimy. The liquid at the top of the tube is some- 

 times a yellowish green but more often brown. This brown color may be 

 confined to a surface layer a few millimeters deep or may extend through- 

 out the liquid medium. In old tubes the fluid is coffee-colored. It is 

 unlike any color in Ridgway, but is somewhat like his moss brown. 



Litmus mii^k. — At room temperature the medium begins to turn 

 slightly blue in 2 days, beginning at the top; and in 5 or 6 days it is fre- 

 quently stratiform, being deepest blue at the top. Reduction begins at 

 the end of a week, the tubes becoming cream-colored throughout, and 

 clearing at the top or showing reduction only at the bottom of the tube 

 for a depth of i cm. or more. There is no curdling, and clearing is com- 

 plete in 2 weeks. At the end of 2 months the tubes are a deep blue-black 

 and sometimes of a gelatinous consistency. At no time is there any red- 

 dening. 



Methylene blue in milk. — In fresh isolations reduction begins in 

 3 days and is completed in 7 days, except for a rim of blue at the top i 

 mm. deep. Curdling takes place in i week; peptonization begins soon 

 after and is completed in 5 weeks, the clear liquid being yellowish to 

 neuvider green, especially toward the top. 



Corn's solution. — Growth is very slight, appearing in 24 hours and 

 increasing slightly the second day. In a week clearing begins, and at the 

 end of 3 or 4 weeks there is no clouding and only a little precipitate. 

 Nonfluorescent. No crystals. 



Uschinsky's solution. — The medium shows light clouding in 24 

 hours. In 48 hours a thin flocculent white film has formed over the 

 surface and shakes down in fine particles. In 4 days there is moderate 

 clouding, a slight surface film, and the medium is a pale turtle green. In 

 2 weeks a heavy white rim has formed around the surface of the liquid. 

 When the cultures are 6 weeks old there is considerable white precipitate — 

 fluid, not viscid — and slides stained in carbol fuchsin show a network of 

 long chains (Pi. 34, C). Fluorescence persists in old cultures. 



Fermi's solution. — Light clouding occurs in 24 hours. In 4 days 

 there is moderate clouding and a delicate surface film which shakes down 

 in fine flocculent particles. In 4 days as much growth as in Uschinsky. 

 In 2 weeks the clouding is heavy, the medium has a greenish tinge, and 

 there is a heavy white surface pellicle 2 to 3 mm. deep, which shakes 

 down in strings of fine white particles. There is considerable white pre- 

 cipitate — a heavy growth. In 3 weeks the white surface pellicle and the 

 precipitate become cream-colored. No chains are formed. Greening 

 first visible after about 2 weeks. At end of a month surface pellicle 

 and precipitate tan color. Clouding and pellicle twice as abundant as in 

 Uschinsky. 



LoefflER's blood serum. — Growth moderate, filiform to slightly 

 undulate, flat, glistening, smooth, medium slightly browned beneath the 

 streak. No liquefaction, not even after 2 months. 



