IMMUNITY AND SUSCEPTIBILITY. 137 



unless some stimulating substance be present. Or the 

 antitoxin itself may be the ferment which brings about 

 a kind of union between toxin and cell — a harmless 

 union — different from that which takes place when the 

 toxin and cell come together. 



A/ode of Administration of Antitoxins. — Whether used 

 experimentally or therapeutically the antitoxins must al- 

 ways be injected subcutaneously or intravenously. Their 

 administration by the mouth is followed by digestion in 

 the intestine, as has been proved by the researches of 

 Carri^re 1 and Paltschikowski. 2 It makes no difference 

 where the injections are made, the flank usually being 

 chosen as a part of the body where the skin is loose and 

 little pressure brought to bear subsequently. There is no 

 gain to be expected from administration in the neighbor- 

 hood of the particular diseased or infected area, as the 

 remedy does not act except through the blood. 



The suggestion of Roux that in the therapeutic ad- 

 ministration of tetanus antitoxin the injection be made 

 into the cerebral substance may have experimental 

 foundation, but is a somewhat questionable procedure. 



Antimicrobic Phenomena. — The protective serums 

 that develop in consequence of immunization to toxins 

 of various kinds do not exert any destructive effect upon 

 bacteria beyond that possessed by the normal serum of 

 the animal used for the experiment. If, however, instead 

 of using bacterial toxins, one produces the forced im- 

 munization by the employment of cultures rich in viru- 

 lent bacteria, the antitoxicity of the serum will vary in 

 proportion to the amount of toxin contained in the 

 culture, and a new phenomenon presents itself in the 

 form of a great intensification of the bacteriolytic prop- 

 erties of the serum. It does not seem to be necessary 

 that virulence plays a very important role in the devel- 

 opment of antimicrobic serums, for as Hueppe produced 

 immunity with bacteria entirely devoid of virulence, it 



1 Annates de 1 " Inst. Pasteur, May 25, 1899, xiii. 

 * Both'n's Krankenhauszeitung, 1898, No. 42. 



