202 A MANUAL OF BACTERIOLOGY 



SCARLATINA. 



This disease is the result of the action of the 

 Micrococcus scarlatince, which has been found in 

 the blood, organs, the exudations and tissues of 

 the ulcerated throat, and in the desquamating epi- 

 demic cells of this disease. M. scarlatince has 

 also been observed in the urine of patients 

 suffering from scarlatina ; and this fluid contains a 

 ptomaine represented by the formula C 5 H 12 N0 4 . 

 The same ptomaine has also been extracted from 

 pure cultivations of Micrococcus scarlatince in pepto- 

 nised gelatine. In fact, the microbe forms this 

 ptomaine from the medium in which it lives. 1 



M. scarlatince^ (0.5 //, diam.) occurs singly, as 

 diplococci, in chains, and in masses (Fig. 33, 9) ; 

 and it grows on the surface of nutrient gelatine, as 

 well as in the depth of that medium. It also grows 

 on agar-agar and in beef bouillon. On nutrient 

 gelatine with slanting surface this microbe forms 

 greyish, circular, flat discs, which ultimately form a 

 grey film. Gelatine tubes inoculated by stabbing 

 show some characteristic features. After twenty- 

 four hours' incubation the surface of the stab 

 appears sunk, and the depression thus formed 

 increases in breadth and depth during the next two 

 or three days, so that by that time there is a 

 distinct funnel-shaped depression indicating the 

 upper end of the channel of inoculation marked as 

 a white streak. Then, commencing at the bottom 



1 See Dr. A. B. Griffiths' paper in Comptes Rendus de I'Aca- 

 ddmie des Sciences, vol. cxiii. (Nov. 9. 1891), p. 656. 



