160 PROTEIN POISONS 



Comparing Table XVII with Tables XV and XVI, it is 

 plainly evident that this immunity induced by two and three 

 doses at intervals of three to four days is greater in degree 

 and more lasting in its effects than that produced by a 

 single injection. This confirms the conclusion already 

 stated, but at the same time this additional work shows 

 that a single dose may serve to furnish protection against 

 at least five times the ordinary fatal dose for a few days 

 and against twice the fatal dose for one month. 



TABLE XVIII 



These animals received a single dose of 100 mg. of the 

 typhoid residue. The protocol number, weight of animal, 

 interval between treatment and inoculation, amount of 

 twenty-four-hour culture given, and the result are shown: 



Amount of 



Protocol, Weight, Interval, culture, 



No. grn. clays. c.c. Result. 



354 250 1 3 Recovery 



355 320 1 4 Death on second day 



356 280 3 3 Death 



357 265 3 4 Death 



358 270 6 2 Death 



359 230 6 . 1 Recovery 

 219 570 28 2 Death 



TABLE XIX 



These animals received a single dose of 50 mg. of the 

 typhoid residue. 



Amount of 

 Protocol, Weight, Interval, culture, 



No. gm. days. c.c. Result. 



336 360 1 3 Recovery 



337 285 3 3 Death 



338 245 7 3 Death 



339 350 9 2 Death on second day 



340 290 11 1 Recovery 



341 255 14 I Recovery 



