SARCINA TETRAGENA. 331 



as small, almost transparent, round points, which have 

 about the same color and appearance as a drop of egg- 

 albumin ; they are very slightly opaque. They are 

 moist and glistening. They rarely develop to an extent 

 exceeding 1 to 2 mm. in diameter. 



Upon agar-agar as stab- or slant-cultures the surface- 

 growth has more or less of a mucoid appearance. It 

 is moist, glistening, and irregularly outlined. The out- 

 line of the growth depends upon the moisture of the 

 agar-agar. It is slightly elevated above the surface of 

 the medium. 



In contradistinction to the gelatin stab-cultures, the 

 growth in agar-agar is continuous along the track of 

 the needle. 



The growth on potato is a thick, irregular, slimy- 

 looking patch. 



The transparent mucilaginous substance which is seen 

 to surround these organisms renders them coherent, so 

 that efforts to take up a portion of a colony from the 

 agar-agar or potato cultures result usually in drawing 

 out fine, silky threads, consisting of organisms imbedded 

 in the mucoid material. 



The organism grows best at from 35 to 38 C., but 

 can be cultivated at the ordinary room -temperature 

 about 20 C. 



The growth under all conditions is slow. 



It grows both in the presence of and without oxygen. 



It is not motile. 



It stains readily with all the ordinary aniline dyes. 



In tissues its presence is readily demonstrated by the 

 staining-method of Gram. 



The grouping into fours is particularly well seen in 

 sections from the organs of animals dead of this form 



