152 PROTEIN POISONS 



this is true, one would suppose that on the injection of a 

 fatal amount of the dead bacterial substance death would 

 occur more rapidly in the immunized than in a normal 

 pig, provided the immune animal possesses a sufficient 

 amount of bacteriolytic substance directly available to 

 cause disintegration of all bacteria present. If, now, a 

 pig which has been immunized with the residue receives 

 5 c.c. of a twenty-four-hour culture of the colon bacillus 

 which has been deprived of life by means of heat, the 

 animal is very sick within from fifteen to twenty minutes. 

 The symptoms noted are similar in all respects to those 

 which are observed after the injection of the soluble poison. 

 The pig runs about the cage, scratches itself, and shows 

 the same evidence of lack of coordination and partial 

 paralysis of the hind extremities. This behavior is in 

 marked contrast to that seen in the case of a normal animal 

 which has received an injection of 5 c.c. of a twenty-four- 

 hour culture which has been rendered sterile by means 

 of heat. In this instance the animal appears perfectly 

 well until after the lapse of about an hour, when it begins 

 to show signs of illness such as roughening of the coat, 

 stupor, and indications of a beginning peritonitis. The 

 latter . symptoms are those which we have described as 

 being due to the slow liberation of the poison from a com- 

 bined state. The same symptoms are observed in the case 

 of the immune pig, and are noticed at the same length of 

 time after the injection. The difference in the behavior 

 of the immune and the normal pig is seen to consist in the 

 fact that in the first instance we have symptoms of the 

 action of the free poison shortly after the injection of the 

 dead culture, which are entirely lacking in the second case. 

 This shows beyond doubt that in the immune pig there is 

 marked bacteriolysis of the dead bacilli and a consequent 

 liberation of the contained poison shortly after the injec- 

 tion of the dead bacterial cell into the peritoneal cavity. 

 Although w r e have as yet been unable to actually cause 

 death in an immune pig at an early period, the animals 

 are in every instance very ill within thirty minutes after 



