BACTERIA AND DISEASE 2?$ 



the non-soluble albumens shall be made into soluble pep- 

 tones and thus become absorbed through the intestinal wall, 

 so also a ferment may be necessary to the production of 

 toxins. Such ferments have not as yet been isolated, but 

 their existence in diphtheria and tetanus is, as we have 

 seen, extremely likely. However that may be, it is now 

 more or less established that there are two kinds of toxic 

 bodies, differing from each other in their resistance to heat. 

 It may be that the one most easily destroyed by heat is a 

 ferment and possibly an originator of the other. A second 

 division which has been suggested for toxic bodies, and to 

 which reference has been made, is intracellular and extra- 

 cellular, according to whether or not the poison exists 

 within or without the body of the bacillus. 



Lastly, we may turn to consider the action of the toxins 

 on the individual in whose body-fluids they are formed. It 

 is hardly necessary to say that any action which bacteria or 

 toxins may have will depend upon their virulence, in some 

 measure upon their number, and not a little upon the chan- 

 nel of infection by which they have gained entrance. It 

 could not be otherwise. If the virulence is attenuated, or 

 if the invasion is very limited in numbers, it stands to reason 

 that the pathogenic effects will be correspondingly small or 

 absent. The influence of the toxins is twofold. In the 

 first place (i.) they act locally upon the tissues at the site of 

 their formation, or at distant points by absorption. There 

 is inflammation with marked cell-proliferation, and this is, 

 more or less rapidly, followed by a specific cell-poisoning. 

 The former change may be accompanied by exudation, and 

 simulate the early stages of abscess formation ; the latter is 

 the specific effect, and results, as in leprosy and tubercle, 

 in infective nodules. The site in some diseases, like typhoid 

 (intestinal ulceration, splenic and mesenteric change) or 

 diphtheria (membrane in the throat), may be definite and 

 always the same. But, on the other hand, the site may 



