THE AMERICAN MONTHLY 



[Jan 



Gelatin plate surface colony, fig. 5, 3 days, x7, and 

 deep colony, fig. 6, 2 days, x60, both are 22 degrees C. 

 In 24 hours the colonies appear as white points. If x60 

 they appear greenish yellow. In 5 days, they become 2 

 to 4 mm in size with a central area and a peripheral 

 zone. 



Figures 7 and 8 show cover-glass preparations from 

 bouillon culture, one x600 and the other xl500, taken 



with Reichert's ocular 4, objective 1-18. At 20 degrees 

 C, the mills sours and curdles after 4-5 days ; at 37 de- 

 grees, there is free growth but no curdling. 



Bacterium lactarii. — This is found constantly in 

 milk that has soured spontaneously, It is oval, single or 

 in pairs. Chains of 4 to 6 each occur. Fig. 13 shows pairs 

 with the attached ends square and rounded. Segmenta- 



