50 PROTEIN POISONS 



"2. Study of the blood serum from animals partially 

 immunized to the germ substance led to the following 

 results : 



" (a) The blood serum of rabbit No. 2, which had received 

 on the twelfth injection 562.3 mg. (1 to 3503), obtained 

 twenty days after the last injection, had no bacteriolytic 

 action on the organisms contained in a beef-tea culture 

 of the colon bacillus of the same strain as that which had 

 been used in immunizing the animals. 



" (6) Tubes of immune serum and others of normal 

 serum were inoculated with virulent cultures of the colon 

 bacillus, and placed in the incubator at 37.5. Both tubes 

 showed good and equal growth within seven hours. 



" (c) Tubes of immune and normal serum were inoculated 

 w r ith virulent cultures of colon and typhoid bacillus, and, 

 from these gelatin plates were made at the end of one 

 minute, thirty minutes, one hour, and forty-eight hours. 

 The number of colonies on the colon plates did not diminish 

 while those on the typhoid plates did with both sera, thus 

 showing that the immune serum had no specific action. 



" (d) Immune serum, when mixed with filtered cultures 

 of the colon bacillus, gives a slight precipitate, which, 

 however, is also given by normal serum. 



" (e) The immune serum gives very positive agglutinating 

 reactions with suspensions of the dead colon germ used in 

 immunizing the animals. Suspensions of from 1 to 50 mg. 

 of the germ substance in 1 c.c. of physiological salt solution 

 are completely precipitated in from three to five minutes 

 on the addition of an equal quantity of immune serum. 

 Control tubes to which normal serum had been added gave 

 negative results, inasmuch as complete subsidence did not 

 occur in these w r ithin fourteen days. 



" (/) The immune serum exerts, when mixed with suspen- 

 sions of the germ substance and injected into the abdominal 

 cavity of rabbits, a slight protective action, as is shown by 

 the following: 



Rabbit No. 1, 850 grams, had 17.0 mg. (1 to 50,000), 2 c.c., I. S., . 

 Rabbit No. 2, 700 grams, had 14.0 mg. (1 to 50,000), 2 c.c., N. S., +. 

 Rabbit No. 3, 840 grams, had 16.8 gm. (1 to 50,000), 2 c.c., beef-tea, +. 



