520 INFECTION AND IMMUNITY. 



lire of leucocytes to take up virulent organisms, 

 whereas non-virulent strains are readily phagooy- 

 tized. Von Lingelsheim states that strains culti- 

 vated from subacute or chronic processes produce 

 more soluble toxin (nature unknown) than highly 

 virulent strains. Not all toxic filtrates contain 

 streptocolysin, the hemolysin being independent 

 of other toxic constituents (Simon). Von Lingels- 

 heim concludes that the infectiousness of strepto- 

 cocci is not explained by the toxic properties which 

 have been demonstrated. He lays stress on their 

 resistance to the bactericidal activities of the tis- 

 sues and tissue fluids. It is safe to say that up to 

 the present time the essential toxin of the strepto- 

 coccus has not been demonstrated. 



Pathologic Streptococci are the frequent cause of wound in- 

 es ' fections, the most common cause of lymphangitis 

 and diffuse inflammations of the subcutaneous and 

 intermuscular connective tissues (cellulitis), endo- 

 metritis and puerperal septicemia, endocarditis 

 and tonsillitis., are often the exciting organisms 

 in pneumonia (lobular, usually), bronchitis, 

 meningitis, inflammations of the serous surfaces 

 (pericardium, pleura, peritoneum joints), enteritis 

 and suppurative processes in the middle ear. They 

 are the exclusive cause of erysipelas, and serious 

 attempts have been made to show that they are 

 etiologic factors in scarlet fever and rheumatic 

 fever. The streptococcus is the most common 

 organism found in the lesions of impetigo conta- 

 giosa, although it may be mixed with other bac- 

 teria, especially the staphylococcus. Occurring a? 

 mixed infections in pneumonia, tuberculosis, scar- 

 let fever, enteritis and other processes, they cause 

 grave and often fatal complications. 



