SUPPURATION, PYjEMIA, SEPTICEMIA, ERYSIPELAS. 179 



The individual elements composing the chains will be found to 

 vary considerably in size : here and there in a preparation will 

 be found a chain composed of excessively small cocci, in another 

 part the elements will be all on a larger scale, and again in 

 another part they will be peculiarly conspicuous on account of their 

 size. So great is the diversity in the size of the cocci in some of the 

 chains, that one might imagine that there was more than one kind 

 of streptococcus present in a preparation, until on examining some 

 of the longest chains it is observed that various sizes are repre- 

 sented in difEerent lengths of the same chain. Very characteristic 

 appearances i-esult from the fact that the cocci enlarge and divide 

 both longitudinally and transversely ; and, indeed, the largest, for 

 the most part, clearly show a division in two directions, resulting 

 in the formation of tetrads. In addition to the forms resulting 

 from the fission of the cocci, there are here and there in a chain, 

 and sometimes terminally, larger elements, which are spherical, 

 spindle-shaped, or in the form of a lemon. In the length of the 

 chains, as in the size of the individual cocci, there is usually great 

 diversity,, In some cases they are composed of only a few, three 

 or four cocci ; in others eight, ten, or twenty. Here and there 

 an exquisite rosary will extend in a straight Hne across the field 

 of the microscope, or be twisted, curved, or serpentine ; in some 

 preparations twisted or entangled strands are observed which are 

 composed of several hundred elements. Such chains will be found 

 to be much thicker in one part than another. Another char- 

 acteristic appearance is produced by separation of the elements 

 resulting from fission in the long direction pi the chain, by which 

 lateral twigs or branches are formed. Another character, which 

 is very striking, may be seen when the individuals in a chain 

 have become separated ; an unstained or faintly stained membrane 

 may be found bridging across the interval. This will become still 

 more visible in preparations contrast- stained with eosin. 



In plate-cultivations the appearances of the colonies are not ver}' 

 striking. They appear to the naked eye after three or four days 

 as extremely minute, greyish-white, translucent dots, which under 

 the microscope have a slightly yellowish-brown colour. They are 

 finely granular and well defined. They do not liquefy the gelatine, 

 and after several weeks may not exceed the size of a pin's head. 



If the surface of nutrient gelatine solidified obliquely be traced 

 over once or twice with a platinum needle bent at the extremity 

 into a little hook charged with the cocci, a ribbon-shaped film 

 develops in two or three days. This film is composed of minute, 



