Io8 MANUAL or BACTERIOLOGY. 



the spheres grow in clusters like a bunch of grapes ; streptococci, 

 where they are arranged in long rows or chains, like a string of 

 beads; diplococci, or pairs of micrococci; tetrads, where the 

 individual spheres are grouped in fours; sarcince, where they 

 are grouped in eights, making the outline of a cube, resembling 

 a bale or package tied with rope. 



Fig. 40. — Bacilli of Vamous Fokms. 



The bacilli are not subdivided in this manner, although their 

 forms vary considerably. The ends are sometimes square, 

 sometimes round. Sometimes they are very short. Some- 

 times they grow in longer, thread-like forms, in which, however, 

 the transverse markings which indicate the outlines of the in- 

 dividual bacilli can generally be seen, and which resemble a 

 bamboo rod. Short, oval bacilli may look exceedingly like 



Fig. 41. — Spirilla of Various Forms. 



micrococci. Bacilli with rounded extremities, placed end to 

 end, look like strings of sausages. Under exceptional circum- 

 stances, branching forms of the bacilli of diphtheria, tubercu- 

 losis, glanders and bubonic plague and various other species 

 have been encountered.* 



* See Hill. Journal oj Medical Research. Vol. VII. January, 1902. Loeb. 

 Ibid. Vol. VIII. 1902. 



