46 
BACTERIOLOGY. 
The streptococcus is one of the group of pus¬ 
forming cocci, characterized by multiplication in one 
plane, producing strings or chains of • cocci. These 
cocci are Gram positive. 
There are many varieties of streptococci which 
may be divided into two large groups depending on 
their faculty of dissolving red blood cells, viz.:— 
1. The hemolytic streptococci. 
2. The non-hemolytic streptococci. 
Numerous individual numbers of these groups 
have been found which vary from one another in their 
shape, staining peculiarities, virulence, and agglutina¬ 
tion reactions. 
The characteristics of the hemolytic group include 
their high degree of virulence and tendency to produce 
epidemic infections. They are rarely present in the 
human body under normal conditions. 
The non-hemolytic streptococci are widely dis¬ 
tributed in the body but they are not so virulent or 
invasive. They rarely are the primary cause of infec¬ 
tion. One member of the non-hemolytic group, the 
Streptococcus viridans, is peculiar in possessing the 
property of changing hemoglobin into methhemoglobin 
when grown on artificial culture-media; the colonies 
have a greenish zone about them. 
Infections with the streptococcus include boils, 
abscesses, erysipelas, puerperal septicemia, septic sore 
throat, broncho-pneumonia, osteomyelitis, mastoiditis, 
meningitis, empyema, and endocarditis. Septic sore 
throat may occur in epidemics and has been traced in 
