no THE ACTION OF ENZYMES 



fluorescent putidus, Fliigge, frequently isolated from putrefying 

 substances, to which it gives a greenish tint and an odour of 

 trimethylamine. The latter is a motile organism, 1.6 to 5 ^ long, 

 .4 to. 6 ^ broad, with one or two flagella only. The surface 

 colonies on gelatine are transparent of coli form, but yellowish- 

 green in colour, and do not liquefy the medium; in other 

 respects the organism agrees with Bact. fluorescens liquefadens. 



7. A common inhabitant of putrefying material is Bs. 

 prodigiosus, a description of which is given on page 282. It 

 sometimes develops bright red blood-like spots on bread, potato, 

 and other starchy foods. 



8. In addition to the organisms previously mentioned certain 

 species of cocci, namely : (i) Micrococcus pyogenes (L. and N.), 

 var. aureus (Staphylococcus pyogenes aureus^ Rosenbach) ; (2) 

 Streptococcus pyogenes, Rosenbach ; (3) Micrococcus flavus, 

 Fliigge, are very frequently present in the early stages of the 

 putrefaction of organic substances. All are widely-distributed 

 organisms. The two former are of special importance to the 

 pathologist, since they are responsible for several inflammatory 

 and suppurative diseases in man. 



(1) M. pyogenes is a coccus from .9 to i /x in diameter, and 

 occurs in irregular clumps or in pairs. It is non-motile, and 

 stains by Gram's method. Growth goes on well at tempera- 

 tures between 27 to 37 C., especially as an aerobe, although it 

 will thrive under anaerobic conditions. The colonies in 

 gelatine are small, whitish or pale yellow, and liquefy the 

 medium. On agar and potato they are whitish at first, but 

 ultimately become a bright orange yellow colour. Milk is 

 coagulated and made acid in a week or less. Bouillon soon 

 becomes cloudy, but finally clears, and deposits a yellow sedi- 

 ment. 



Several varieties are met with, some of them differing in 

 the production of lemon-coloured (var. citreus) or white colonies 

 (var. albus). 



(2) Streptococcus pyogenes occurs in the form of long chains, 



