160 The Story of the Bacteria 



toxin for the diphtheria bacillus poison, for 

 example, would not at all protect against the 

 tetanus poison, or vice versa. 



As soon as research had gone thus far into 

 the problem of immunity, the thought of the 

 lonesome worker in the laboratory turned, as 

 it is wont to do, with every new outlook, 

 toward the needs of suffering mortals. If 

 in the body of an infected animal, as is the 

 case in man, this protective antitoxin may 

 be formed in excess so ran the thought of 

 the investigator might it not be possible 

 to treat animals with special forms of bacteria 

 or their poisons, and when their cells have been 

 educated to the overproduction of the specific 

 antitoxin, draw off some of the blood con- 

 taining it, and by introducing this into the 

 body of a human victim of the disease, save 

 him from impending death by poison? This 

 significant and humane suggestion has been 

 worked out into a practical system. And 

 now the world over are laboratories from which 

 are derived life-saving antitoxins of various 

 kinds. 



Among these the first to be secured and the 



