34 



virulence. None of the sera, however, has conferred complete 

 protection against any but the homologous strain, though some- 

 times mice have only succumbed to pneumococcal septicaemia 

 8 and 10 days after inoculation. This delay I am inclined to 

 attribute not to specific protection, but to an increased general 

 resistance induced by the intraperitoneal injection of serum 

 protein. 



A few strains, e.g., Pn. 30, Pn. 46 and Pn. 10, which were of 

 the same agglutination type, and Pn. 9, were almost equal in 

 height and regularity of virulence to the Type I and Type II 

 strains, and some protection experiments made with them have 

 given satisfactory results. The test sera were inoculated in the 

 evening, in doses of 0*2 c.c, and were followed by the test 

 cultures the following morning. All the inoculations were made 

 intraperitoneally, with broth diluted to 0-5 c.c. 



Tables showing Results of Protection Tests v. Pn. 30 



and Pn. 46. 



Serum 

 (0-2c.c.) 



Test Culture. 



Result. 



Test Culture. 



Result. 



Pn. 4(i 



Pn. 10 



Pn. 26 



I'n. 42 



Type I 



Type H 



Typa III 



1 c.c. 

 1 c.c. 

 01 c.c. 

 001 c.c. - 



1 c.c. 

 1 c.c. 

 01 c.c. 

 001 c.c. - 



000 01 c.c. 

 000 001 c.c. 

 OOOOOOlc.c. 



000 01 c.c. 

 000 001 c.c. 

 OOOOOOlc.c. 



000 01 c.c. 

 000 001 c.c 

 OOOOOOlc.c. 



000 01 c.c. 

 000 001 c.c. 

 OOOOOOlc.c. 



000 01 c.c. 

 000 001 c.c. 

 OOOOOOlc.c. 



Survived 



Survived 



D. 2 days 

 D. 2 days 

 D. 2 days 



D. 2 days 

 D. 2 days 

 D. 2 days 



D 2 days 

 D 2 davs 

 D. 2 days 



D. 2 days 

 D. 2 davs 

 D. 2 days 



D. 2 days 

 D. 2 days 

 D. 2 days 



1 c.c. 

 01 c.c. 

 001 c.c. - 

 0001 c.c. - 



1 c.c. 

 01 c.c. 

 001 c.c - 

 0001 c.c. - 



0001 c.c. - 

 000 01 c.c. 



000 001 c.c, 



0001 c.c. - 

 000 01 c.c. 

 000 001 c.c. 



000 01 c.c. 

 000 001 c c 

 OOOOOOlc.c. 



000 01 c.c. 

 000 001 c.c. 

 OOOOOOlc.c. 



000 01 c.c. 

 000 001 c.c. 

 000 OOOlc.c. 



Survived. 



Survived. 



D. 2 (lavs. 

 D. 2 davs. 

 D. 2 days 



D. 2 days 

 D. 2 days 



D. 2 days 



D. 1 day. 

 D 2 day*. 

 D. 2 days. 



D. 1 day. 

 D. 2 days. 

 D. 2 days. 



D. 2 (lav-. 

 D. 1 day. 

 D. 2 days. 



The control mice inoculated with Pn. 30 culture in doses of 

 0-000 001 c.c, 0-000 000 1 c.e. and 0-000 000 01 c.c. died in two days. 

 A similar result was obtained with Pn. 46 culture. 



