130 PATHOGENIC BACTERIA. 



enzyme, for there was, as has been shown, 327 times as 

 much energy in the horse's blood as had been introduced 

 in the form of toxin or enzyme. 



C. Theory that the antitoxin is a product of cytic 

 activity. — As the antitoxin cannot be a changed form 

 of the toxin introduced into the immunized animal, and 

 as it is not a power normal to the blood, its origin must 

 be sought for elsewhere. All experiments directed 

 toward finding any tissue storehouse from which the 

 antitoxin is passed into the blood have failed. It is, 

 however, present in the blood, in the tissue juices, and 

 in the majority of the secretions, into which it enters 

 from the blood. 



Probably the best explanation of the histogenesis of 

 the antitoxin is contained in the theory of Ehrlich, 1 

 which has become well known as the " Seiten-ketten 

 Theorie" or "Lateral chain theory." According to 

 Ehrlich' s view, the cells of the body are to be looked upon 

 as of complex molecular structure, and as possessing 

 numerous " lateral chains " which have varied combining 

 powers. 



When toxin in increasing amounts is introduced into 

 the body the cells are stimulated to regenerate that part 

 of their structure with which it enters into combination, 

 and to produce it in excess of the probable future needs. 

 In this manner there is produced by the cells and poured 

 into the blood a considerable quantity of toxin-combin- 

 ing substance, which appears to us as antitoxin. The 

 formation of this substance seems to be a new and per- 

 sistent secretory property of the cells, according to the 

 experiments of Thiele and Wolf, 2 but experience has 

 taught that it is by no means permanent, but begins to 

 wane as soon as the stimulation of the toxin is withheld. 



Specific Action of the Antitoxins. — The protection 

 afforded by diphtheria antitoxin seems to be exerted 

 against diphtheria cultures and toxins only, so that the 

 early experimenters easily fell into the error that each 



1 Klinisches Jahrbuch, 1897. * Archiv fur Hygiene, 34, Heft I. 



