STREPTOCOCCI 31 
description and the failure of the authors to mention any character 
or property, or combination of the same, which would distinguish 
them from each other. 
Classification of streptococci. A few investigators have tried to 
eliminate the confusion concerning species by classifying streptococci 
according to distinct morphologic characters and pathogenic proper- 
ties. More recently several investigators have attempted to classify 
them according to their cultural properties, especially their action 
upon the sugars. The studies of Kurth, Pasquale, von Lingelsheim, 
Andrews and Horder and Winslow, Palmer and Broadhurst are 
worthy of careful consideration in this connection. 
Distribution of streptococci in nature. The fact has been pointed 
out in many publications that streptococci are quite widely dis- 
tributed in nature. The results of the bacteriologic examinations of 
normal mucous membranes show that they are frequently included 
‘in the bacterial flora of the mouth, throat, nares, intestines, vagina, 
and in a few cases they have been found in the bronchioles of the 
horse and rabbit. They are also present in greater or less numbers 
on the skin, especially in the deeper layers, presumably in the ducts 
of the sweat and sebaceous glands and along the hair shafts and 
follicles. This explains their frequent appearance in certain wound 
infections. They have been found in soil and in water, and occasion- 
ally these forms are quite as delicate in their morphology and equally 
as sensitive to the influence of environment as those isolated from 
diseased animal tissues. In view of their wide distribution, the 
presence of streptococci in morbid tissues cannot be considered neces- 
sarily as specific infections. In many diseases, such as diphtheria 
and tuberculosis, streptococci frequently appear in the lesions. In 
these cases, they are accidental or secondary invaders, although in 
some of these maladies, such as tuberculosis, they are believed to be 
of more or less importance. When, however, the specific cause of 
the disease is not positively known, and streptococci which possess cer- 
tain pathogenic powers for experimental animals are constantly 
present, the pathologist is confronted with a puzzling problem in 
trying to determine their etiological importance. In streptococcic 
infection leading at once to bacteriemia, peritonitis or suppuration, 
the explanation is more simple than in the epizodtic diseases, such as 
Brustseuche, where the presence of streptococci in the lesions can be 
quite as easily explained on the ground of their invasion of the parts 
