38 BACTERIOLOGY. 



The micrococci are subdivided according to their 

 grouping, as seen in growing cultures, into staphylococci 

 those growing in masses like clusters of grapes (see 

 Fig. 1, a) ; streptococci those growing in chains con- 

 sisting of a number of individual cells strung together 

 like beads or pearls upon a string (see Fig. 1,6); 

 diplococci those growing in pairs (Fig. 1, o); tetrads 

 those developing as fours (Fig. 1, d) ; and sarcince 

 those dividing into fours, eights, etc., as cubes that is, 

 in centra-distinction to all other forms, the segmenta- 

 tion, which is rarely complete, takes place in three 

 directions of space, so that when growing the bundle of 

 segmenting cells presents somewhat the appearance of 

 a bale of cotton (Fig. 1, e). 



To the bacilli belong all straight, rod-shaped bacteria, 

 i. e., those in which one diameter is always greater than 

 the other. 



FIG. 4. 



*" 



a 5 c d 



a. Bacillus subtilis with spores, b. Bacillus anthracis with spores, c. Clos- 

 tridium form with spores, d. Bacillus of tetanus with end spores. 



In this group are found those organisms the life cycle 

 of many of which presents deviations from the simple 

 rod shape. Many of them in the course of development 

 increase in length into long threads, along the course of 

 which traces of segmentation may usually be found 

 the anthrax bacillus and bacillus subtilis are conspicuous 

 examples of this. Again, under certain conditions, 

 many of them possess the property of forming within 



