TEXT-BOOK OF BACTERIOLOGY. 319 



The streptococci of erysipelas are small, completely round, glob- 

 ular cells possessing a pronounced tendency to grow into long 

 chains. They always appear, in the culture as well as in the tis- 

 sue, in extended, bead-like chains, embracing generally six to ten, 

 but frequently even hundreds, of members. These chains often 

 interlace in a dense coil or form elegantly arranged bundles. The 

 single cells are of uniform size, though once in a while some mem- 

 ber, on the point of dividing, is of a somewhat greater size. 



The erysipelas cocci are immobile and have no spores. They 

 thrive at common room-temperature, more rapidly of course at 

 higher degrees (30 to 37 C.). They are not particularly sensitive 

 to want of oxygen, but thrive best on the surface of the artificial 

 media with free access of air. They are easily stained by the vari- 

 ous anilin dyes and, like most micrococci, prove readily accessible 

 to Gram's double staining. 



Their growth on the gelatin plate is rather slow and circum- 

 scribed. They may usually be noticed with the naked eye, on the 

 third or fourth day, as small white dots in the depth of the gela- 

 tin; they never grow beyond the size of a pin's head, never liquefy 

 the gelatin, and do not even advance to the surface. 



The colonies under the microscope appear as round, yellowish- 

 brown heaps, with sharp and smooth edges and of a strangely-gran- 

 ular structure of layers sometimes distinctly ring-shaped. 



Their development is most rapid on agar-plates kept at breeding 

 temperature. As early as the second day there arise extremely 

 delicate, transparent aggregations of gray color and in the form 

 of drops, generally not exceeding a moderate size. 



The growth of erysipelas cocci in the gelatin culture is quite 

 characteristic. The entire extent of the inoculation puncture is 

 slowly studded with very small white and globular granules gen- 

 erally remaining isolated and presenting an appearance nearly like 

 Fraenkel's pneumonia bacteria. The inoculation on oblique gela- 

 tin or agar appears the same; in its neighborhood numerous tiny 

 round drops appear that do not coalesce and reach only a small 

 size. 



The same is the case on blood-serum. A distinct development 

 cannot be observed on potatoes. 



For the purpose of obtaining large quantities of erysipelas cocci 

 and keeping on hand sufficient material for cultures, cultivation in 

 bouillon is preferable; in this there quickly develops, at breeding 

 temperature, a very luxuriant growth of beautiful chains of micro- 

 organisms sinking to the bottom in whitish, crumbling flakes, while 

 the nourishing fluid remains clear. Only a vigorous shaking of the 



