DESCRIPTION OF PLATE IV. 

 Streptococcus Pyogenes. 



Fig. 1. — From a, cover-glass preparation of pus from a pyjemic abscess. 

 Stained with gentian-violet by the method of Gram, and contras1>stained 

 with eosin. x 1200. Powell and Lealand's apochromatic ^V 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 apochromatic f^ Horn. imm. B. P. 10. 

 In 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. 

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



average size, 

 (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 same chain. 



