274 STREPTOCOCCUS-PNEUMOCOCCUS GROUP 



M'Nee, 1 and Lyall 2 have studied the conditions favoring the formation 

 of the hemolysin and find that sugar-free ascitic broth is suitable for 

 this purpose. The substance is thermolabile and is found in an active 

 state only during the first twelve to twenty-four hours of culture, 

 at which time small amounts of sterile (filtered) broth, 0.01 to 0.10 

 c.c., are strongly hemolytic. The hemolysin does not induce antibody 

 formation when it is iniected into susceptible animals. Hemoglobin- 

 emia and hemoglobinurea are produced in rabbits that are very sus- 

 ceptible to the hemolysin; less susceptible rabbits react but slightly. 

 There is no definite evidence that streptocolysin plays a prominent 

 part in the streptococcus infections of man. Virulence and hemolytic 

 activity are frequently, but by no means necessarily, parallel pheno- 

 mena. 



Distribution in Nature. Streptococci are widely distributed in nature, 

 always, however, in rather intimate association with man or the 

 higher animals. They are found in the soil, water, milk, and they 

 exist as "opportunists" on the exposed surfaces and mucous mem- 

 branes of man. They are common in the mouth, nose and throat, the 

 intestinal tract, and rare in the normal vagina. 



Pathogenesis. Human. Streptococci excite both local inflam- 

 matory and suppurative processes and generalized septicemic infec- 

 tions, the latter being the more common and characteristic. Super- 

 ficial lesions may be mild in character, resembling those caused by 

 staphylococci. The organisms may, and frequently do, enter the 

 blood or lymph channels, and spread rapidly through the body, incit- 

 ing the most severe generalized infections. Streptococci are the etio- 

 logical agents of erysipelas, frequently of general and puerperal sepsis 

 and phlebitis, and inflammations of the internal organs; of these, 

 the middle ear, the endocardium, the peritoneum, the meninges or 

 joints are more commonly involved. 3 Escherich 4 and others have 

 described a severe type of enteritis, particularly of young children- 

 streptococcus enteritis which occasionally exhibits an epidemic 

 tendency in the summer months. 5 Attention has been directed in 

 recent years to severe epidemics of septic sore throat in which the 



1 Ibid., 1913, xvii, 524. 



2 Jour. Med. Research, 1914, xxx, 487. 



3 Menzer, Deut. med. Wchnschr., 1901, 97. Meyer, Zeit. f. klin. Med., 1902, xlvi, 

 311; Internal. Beitrage zur inn. Med., 1902, ii, 443. Philipp, Deut. Arch. f. klin. 

 Med., 1903, Ixxvi, 150. Poynton and Payne, Cent. f. Bakt., Orig., 1902, xxxi, 502. Cole, 

 Jour. Inf. Dis., 1904, i, 714. Rosenow, Jour. Inf. Dis., 1910, vii, 411; ibid., 1912, xi, 

 210; Jour. Am. Med. Assn., 1913, Ix, 1223. 



4 Jahrb. f. Kinderheilk., 1899, xlix, 137. 



6 Kendall, Day and Bagg, Boston Med. and Surg. Jour., 1913, clxix, 741. 



