DESCRIPTION OF PLATE IV. 

 Streptococcus Pyogenes. 



FIG. 1. -From a cover-glass preparation of pus from a pyaemic abscess. 

 Stained with gentian-violet by the method of Gram, and contrast-stained 

 with eosin. x 1200. Powell and Lealand's apochromatic -^ Horn. imm. 

 E. P. 10. 



FIG. 2. From cover-glass preparations of artificial cultivations of the strepto- 

 coccus in broth and in milk at different stages of growth, x 1200. Powell 

 and Lealand's apocbromatic ^ Horn. imm. E. P. 10. 



Jn these preparations there is a great diversity in size and form of the 

 chains and their component elements. In the drawing examples are 

 figured of the following: 



(a) Branched chains. 



(b) Simple chains composed of elements much smaller than the 

 average size. v 



(c) Chains with spherical and spindle-shaped elements at irregular 

 intervals. These are conspicuous by their size, and are sometimes 

 terminal. 



(d e) Chains in which the elements are more or less uniform in size. 

 (/) Complex chains with elements dividing both longitudinally and 



transversely, and varying considerably in size in different lengths 



of the sam.e chain. 



