454 PATHOGENIC MICROORGANISMS 



coccus group is still open to question. E. C. Rosenow 49 has recently 

 reported that he has transmuted typical pneumococci into typical 

 hemolytic streptococci by methods which he has not as yet fully 

 described, but among which were animal passage, growth in symbiosis 

 with bacillus subtilis, and growth in an atmosphere of oxygen. The 

 pneumococci when first altered took on the characteristics of the 

 streptococcus viridans, later of the so-called streptococcus rheumaticus, 

 and finally of streptococcus hemolyticus. Together with cultural 

 characteristics the pathogenicity of these various strains for rabbits 

 changed. The pneumococcus produced acute sepsis, the streptococcus 

 viridans caused endocarditis, the streptococcus rheumaticus peri- 

 articular or serous arthritis, and hemolyticus suppurative arthritis. 

 In intermediate stage the organisms quite regularly caused myositis. 

 Although he was able to transmute these types one into the other in 

 both directions, Rosenow believes that the cultural characteristics of 

 each type correspond to a fairly definite type of pathogenicity in ani- 

 mals and man. This work has not as yet appeared in detail and has 

 not been confirmed. 



Toxic Products of the Pneumococcus. Our knowledge of pneu- 

 mococcus poisons is still very imperfect. Attempts to obtain soluble 

 toxins by the filtration of cultures have been practically unsuccessful. 

 G. and F. Klemperer, 50 Mennes, 51 Pane, 52 Foa and' Carbone, 53 and 

 others failed to obtain pneumococcus filtrates of any degree of toxicity, 

 though working with highly virulent strains. The feeble toxin so 

 obtained produced no antitoxin. 



The general failure to procure strong soluble poisons from cultures, 

 gives weight to the assumption that the most potent toxic products of 

 pneumococci are in the nature of endotoxins and closely bound to the 

 cell-bodies themselves. This assumption is borne out by the more 

 recent experiments of Macfadyen. 54 This author obtained acutely 

 poisonous substances from pneumococci by trituration of the organ- 

 isms after freezing, and extracting them with a one 1 :1,000 caustic 

 potash solution. With the filtrates of these extracts he was able to 

 cause rapid death in rabbits and guinea-pigs by the use of doses not 



Eosenow, J. A. M. A., 1913, Ixi, 2007. 



50 G. and F. Klemperer, Berl. klin. Woch., xxxiv and xxxv, 1891. 

 "Mennes, Zeit. f. Hyg., xxv, 1897. 



K Pane, Eif. med., xxi, 1898. 



53 .Foa und Carbone, Cent. f. Bakt., x, 1899. 



51 Macfadyen, Brit. Med. Jour., ii, 1906. 



