THE PHENOMENA OF INFECTION 469 



reported cases patients have before death remarked on their 

 inability to walk. 



It is quite evident from a study of the untoward results 

 following the administration of horse serum, that the 

 apparent differences existing between immediate mani- 

 festations and those occurring after an incubation period 

 of from seven to ten days are of degrees of intensity rather 

 than of character of the poisoning. Thus, in the instances, 

 fortunately rare, in which death occurred within thirty 

 minutes following the injection, the symptoms are due to 

 the liberation of a fatal amount of poisonous substance at 

 once, and in instances in which alarming but not fatal 

 symptoms arise shortly after injection, recovery from the 

 intoxication is usually prompt and complete. On the other 

 hand, where symptoms appear only after an interval of 

 from seven to ten days, and are confined to those of peripheral 

 irritation, as evidenced by the development of urticaria, 

 we find that complete recovery is slow and tedious. 



That such differences should exist appears but natural 

 when w r e consider the mechanism involved in sensitization, 

 and the fact that immediate effects are due to the injection 

 of the serum into a sensitized individual, whereas the remote 

 effects are to be looked upon as a manifestation of the 

 sensitization of the patient as the result of the injection 

 itself. In the first instance the individual has stored up in 

 his body cells a ferment which, liberated by the injection 

 of the serum, splits up the foreign protein introduced at 

 once, and sets free all of the poison contained therein imme- 

 diately. The symptoms resulting therefrom are necessarily 

 acute in character, sudden in development, and transitory 

 in nature, since the effects of the poison rapidly disappear. 

 In the individual developing symptoms after an incubation 

 period of from seven to ten days, conditions are decidedly 

 different. In this case no special ferment capable of pro- 

 ducing proteolysis of the foreign proteins contained in 

 the serum is present within the body at the time of injec- 

 tion, and as a result the foreign proteins continue to 

 exist as such ^within the body for a certain length of time. 



