29 



Thus, 49 strains of pneumococci from 47 cases of respiratory 

 disease (34 of which were from lobar pneumonia and 15 from 

 other diseases) fall into 12 distinct serological types : 20 strains 

 belong to the American types IIa and IIb, which are the pre- 

 dominating types in what I propose to call Group IV; and in 

 one type, Pn. 84, there is only a single representative, namely, 

 that from which the serum was prepared. 



In two cases it will be noticed that two different types were obtained 

 at different stages of the disease. From case 32 a pneumococcus of Type 

 Pn. 87 was obtained from the sputum during the acute stage of pneumonia : 

 a month later the patient died and at the post-mortem examination there 

 was found necrosis of the lung, with cavity formation, from which Type IIb 

 was obtained. 



The second case, No. 152, was in the sixth day of lobar pneumonia 

 when the sputum was examined and yielded Type Pn. 10. On the 12th 

 day of the disease, and again on the 19th, a strain of IIb was obtained in 

 pure culture from the sputum through the mouse : four colonies were 

 examined from the 12th clay specimen and 14 colonies from the 19th day 

 and were all Type IIb. This question of different types of pneumococci 

 from the same sputum is discussed later. 



