502 THE WONDER OF LIFE 



cases) invulnerable or ' immune ' so far as that particular 

 poison is concerned. In conquering the poison of the 

 disease the body produces anti-toxins, which remain as a 

 chemical body-guard, preventing the same disease from 

 getting in again. In a similar way the anti-toxin 

 produced as a reaction to the mild poison introduced in 

 vaccination is a preventive or an immunization against 

 subsequent poisoning from small-pox. This is the first 

 point to be apprehended. 



It is also very well known that there are many poisons, 

 such as the nicotine of tobacco, which render the individual 

 increasingly tolerant of them if their use is persisted in. 

 Thus, the confirmed ' opium-eater ' can imbibe or inject 

 a dose which would immediately kill a normal individual, 

 and which would have been fatal to himself if he had not 

 accustomed himself to gradually increased quantities. De 

 Quincey, in his Confessions, tells us that he gave to a 

 wandering Malay who came to his door, a piece of opium 

 large enough to kill six dragoons and their horses if they 

 were not used to it ! The Malay received it with delight, 

 broke it into three pieces, and immediately swallowed 

 them all. De Quincey's own allowance at one period of 

 his life was said to be eight thousand drops of laudanum a 

 day. In any case, it is certain that the body becomes 

 increasingly tolerant of certain poisons. 



Anaphylaxis. The new fact which has been discovered 

 by the eminent French physiologist, Professor Charles 

 Richet, is that certain poisons when introduced into the 

 system enormously increase the susceptibility of the organ- 

 ism to the toxic action of that particular substance. This fact 

 was apparently not unknown to some of the earlier 

 physiologists, but it was not clearly recognized as other 



