PHYSICAL AND CHEMICAL AGENTS 45 



ptomains being the poisonous products resulting 

 from the action of bacteria in the decomposition of 

 organic matter, and toxins are the poisonous sub- 

 stances produced by the bacteria themselves. 



Many epidemics of food poisoning which were 

 formerly attributed to ptomains are now believed to 

 be due to the presence of some special organism. 



Pathogenic bacteria produce disease by their 

 action upon the animal tissues in which they find 

 lodgment ; this poisonous action may be due to the 

 toxins produced by the bacteria, or to the poisonous 

 material of which the germs are composed (endo- 

 toxins). Some species produce soluble poisons 

 which are easily separated from the organisms them- 

 selves, while others are found to contain proteid 

 matters in their own bodies which are highly toxic, 

 and these we know as endotoxins. 



The potency (strength) of some of the bacterial 

 toxins far exceeds that of any other known poisons ; 

 for instance, the toxin produced by the bacillus of 

 tetanus (lockjaw) is more than a thousand times as 

 powerful as strychnine. 



