IV 



normal agglutinating power of 12,5 pr. cc. (total 20838), 

 these 2067 cc. of serum contained 100838 units, and one 

 1 cc. should after the calculation have 48,8, while the 

 experiment gave 50. 



It appears from the table, that the calculated values as a 

 rule correspond very well to those observed. That the 

 latter generally are somewhat lower is probably due to 

 the circumstance, that the samples of blood could not 

 always be taken immediately after the injection. This 

 concerns especially the rabbits, where the bleeding al- 

 ways takes some time, in which the rapid decrease of 

 agglutinating power will be noticeable. 



The typhoid and cholera agglutinins may thus be 

 considered as simply diluted in the blood of the ani- 

 mal, into which they are injected. 



After the separate examination of active and pas- 

 sive immunisation we proceeded to study a combina- 

 tion of both. 



The first experiment in that way concerned the goat, 

 which is mentioned on curve No. 6. The agglutinating 

 power of the blood, completely disappeared on the 19 / 5 , 

 was again increased on the VG by means of an injection 

 of 200 cc. cholera agglutinin from goat. On the 3 / G , when 

 the agglutinating faculty had decreased to 2.8, 75 cc. 

 48h culture of Vb. cholerae was injected. In a fresh 

 animal this injection had invariably produced the curve, 

 which is typical for the active immunisation ; but in this 

 case no change at all took place, and the agglutinin con- 

 tinued a gradual decrease during the following days. 



The object of the next experiments was to demon- 

 strate, that the nature of the employed agglutinin had 



28 



