430 ACTINOMYCETES. 



Gelatin Plate. — In young cultures the colonies are 

 very similar to the Bact. coli macroscopically; later the 

 colonies are more wrinkled. When magnified sixty times, 

 they present a wavy, scalloped border with more or less 

 wrinkling internally, being very similar to old colonies of 

 the Bact. coli (64, vi, a). The deep colonies are not 

 characteristic (64, vi, b). 



Glycerin-agar Plate. — Macroscopically at first small, 

 crumbly colonies, which later become wrinkled and ele- 

 vated, and still later usually present a delicate transparent 

 peripheral zone (64, ix). Magnified sixty times the colo- 

 nies are usually pronouncedly granular, always becoming 

 more transparent toward the periphery, and in this latter 

 zone often present proteus-like markings (64, viii). 



Glycerin-agar Streak. — After six days at 37° a dirty 

 grayish-white growth with a wavy smooth border, a fatty 

 luster, numerous more or less elevated folds, and trans- 

 parent in many places (64, n). Sometimes the wrinkling 

 from the beginning is not so outspoken, the surface being 

 much more homogeneous, and after many weeks it is of a 

 yellow to a coppery red color. The consistency of the 

 growth at first is like butter, later like saliva, and not 

 crumbly and dry (64, in). Upon ordinary agar there 

 later occurs a brownish-yellow coloration and little wrink- 

 ling (64, i). 



Gelatin Streak Culture. — The growth was somewhat 

 thinner and more delicate, the wrinkling more pronounced 

 and regular. A decided orange color did not develop. 



Bouillon Culture. — At first turbid, later clear. A 

 pellicle is sometimes formed. The precipitate is moderate 

 and yellowish- white. In sugar bouillon growth is more 

 luxuriant, with almost constantly a thick wrinkled pelli- 

 cle on the surface, the sediment being abundant and dis- 

 sociated with difficulty. Milk is not coagulated, but after 

 a time it becomes transparent and sometimes gelatinous. 

 At the edge a bright orange pigment is deposited. 



Potato Culture. — Slightly elevated, more or less wrin- 

 kled, often also a homogeneous growth, with notched or 

 smooth border; when older, there are knobby elevations, 

 the growth being bright to deep orange, with a fatty or 

 moist luster (64, v). 



