4o8 Bulletin 165. 



individuals are either spherical in form or short rods exhibiting 

 the various stages of segmentation. 



There is a great variation in size depending upon the medium 

 and age of the culture. In an agar slant eight days old the 

 spherical forms vary from .6 to .S /x. in diameter, while the elon- 

 gated forms which predominate in numbers vary from 8.. to 1.2 

 /i. in breadth and from 1.2 to 2 /x. in length. In a bouillon cul- 

 ture three daj^s old great variation in size occurs, the predom- 

 inating form measuring i to 2 p.. in breadth and from 2 to 3 /j.. in 

 length. 



In all old cultures forms occur which differ wndelj^ from those 

 in growing cultures. Involution forms, approximately circular 

 in outline and measuring from 2 to 3 />t. in diameter, may appear 

 singly or in pairs. Rods measuring about 1.2 /a. in width and 

 from 2 to 4 /J-. in length are occasionall}^ present. Long chains 

 are frequently found in cultures three weeks old. Some thread 

 like forms occur which show no indication of division into sep- 

 arate individuals. 



The organism stains readily with the aniline dyes in common 

 use. It exhibits an irregular arrangement of the cellular pro- 

 toplasm when stained with carbol fuchsin. This feature is more 

 or less noticeable in individuals from all of the culture media, but 

 is most conspicuous in bouillon (See plate). When treated by 

 the Gram method the stain is retained. The capsule does not 

 stain when treated by the common methods, but preparations 

 made from milk by extracting the fat with ether and staining 

 with carbol fuch.sin show the capsule especially well as an 

 unstained area surrounding each individual. The presence of 

 the capsules can be positivel}' demonstrated by Welch's glacial 

 acetic acid method and by the Gram method. 



The organism proVjably possesses slight motility, but the 

 motion is so feeble that it is with difficulty distinguished from 

 the Brownian movement. Motility is best observed in young 

 milk cultures. The viscid nature of the growth presents diffi- 

 culties which may have prevented the demoUvStration of fiagella. 

 In view of the uncertaint}- concerning the presence of motility 

 this is unfortunate. 



Biologic characters, — This bacillus is a strict aerobe. It grows 



