UDDER-STREPTOMYCOSIS 41 



gelatin-agar (gelatin 5 per cent., agar 0.75 per cent., and 

 serum 15 per cent., the latter is added shortly before pour- 

 ing) . This medium is very soft and the colonies maintain a 

 characteristic form. After one day at 38° C. the colonies 

 manifest small, grayish-white visible points, and after a 

 few days a few sparse colonies in the last plate reach the 

 size of ca. half a pinhead. These dis- 

 tinct colonies are deep colonies. Under 

 the microscope they are round or oval 

 and as a rule have an uneven, jagged fiq. 7— colonies of 



rt i n ' 1 • 1 • ^ ' • n streptococci. Deep colonieB. 



or nnelv irmered marmn which is mire- serum- gelatin -agar piates. 



.1 /T^- ^\ rr>l 1 • T. 38° C. 3 days. (X30). 



quently even (Fig. 7). Ihe colonies 

 which reach the surface show a round, bluish-gray, thin, 

 barely visible membranous surface growth the size of a 

 hemp seed. These surface colonies are sparsely present 

 and may be absent altogether. 



With stab cultures in gelatin-agar, agar (38°) and 

 gelatin (20°), a grayish- white gi-anular filament forms 

 along the line of puncture and as a rule there is no distinct 

 surface growth (Fig. 8). The gelatin is 

 not liquefied. Growth at 20° C. is slow. 



With streaks upon agar, coagulated 

 serum (38°) and gelatin (20°) small, fine 

 grayish-blue colonies like drops of moisture 

 \y form along the streak and then coalesce, pro- 



of ^sTrept^^Jocci" ducing a fine thin filament. 

 feiatin-igar''T"?8» Upon. potato (38°) thc strcptococcus 

 c. 3 days. grows slowly without forming colonies that 



are visible to the naked eye. 



In bouillon the streptococci form grayish-white bac- 

 terial granules or colonies the size of a pinhead on the bot- 

 tom and along the side of the test tube. The media does 

 not become turbid. Upon shaking the test tube the colo- 

 nies are destroyed and the bouillon is made uniformly 

 turbid. 



