CLASSIFICATION OF PNEUMOCOCCI 125 



to 55°, and observed a more or less opaque contact ring when the 

 antigen and antiserum were of the homologous type. Here again 

 there were some failures due to the quality of the sputum, but with 

 the majority of specimens the method gave a rapid and accurate 

 type diagnosis. 



The Krumwiede method was given a trial by Kohn 737 with a lim- 

 ited number of cultures. The results, in the main, agreed closely 

 with those obtained by the mouse-protection test. Because of ac- 

 curacy, simplicity, and the saving of time and mice, Kohn advised 

 its more general adoption. 



A somewhat unusual case was reported by Gilbert and Daven- 

 port 514 which called attention to the complication presented by the 

 occurrence in sputum of pneumococci of more than one fixed type. 

 The Krumwiede test was negative with the three type serums. The 

 culture in the Avery medium showed a faint reaction with Type I 

 serum but none with that of Types II and III. A mouse inoculated 

 with the sputum was dead at the end of forty-eight hours and the 

 agglutination, precipitation, and cultural tests all showed the sole 

 presence of Type III Pneumococcus. Direct planting of the spu- 

 tum and of the Avery culture on blood plates yielded a predomi- 

 nance of green-producing cocci, which culturally proved to be 

 Type I organisms and S. viridans. Serologically the growth ag- 

 glutinated with both Type I and III serums. 



Another avenue of approach was that reported by Loewe, 

 Hirschfeld, and Wallach. 821 Instead of searching for precipitino- 

 gen in the excretions of pneumonia patients, they sought precipitin 

 in the blood. The blood was drawn into potassium oxalate, laked 

 with ether, and added to saline suspensions of type strains of pneu- 

 mococci grown on glucose-serum agar. The mixtures were incu- 

 bated until a color change due to alteration of the hemoglobin ap- 

 peared. Inasmuch as immune substances do not usually appear in 

 the blood stream in the very early stages of pneumonia, it is diffi- 

 cult to see how this method could possess any advantage over those 

 aimed to detect the presence of precipitinogen in the urine or blood. 



