THE TOXINS PRODUCED BY BACTERIA. 1 71 



in most bacterial infections no doubt contributes to the rise of 

 bodily temperature. But we must bear in mind that in fever 

 there is more than mere increase of heat production — there is 

 also a diminished loss of heat from interference with the nervous 

 mechanism of the sweat apparatus. The known facts would 

 indicate that in fever there may be a factor involving the nervous 

 system to be taken into account. The whole subject is thus very 

 obscure. 



Symptoms. — Many of the symptoms occurring in bacterial 

 affections are produced by the histological changes mentioned, 

 as can be readily understood ; whilst in the case of others, corre- 

 sponding changes have not yet been discovered. Of the latter, 

 those associated with fever, with its disturbances of metabolism 

 and manifold affections of the various systems, are the most 

 important. The nervous system is especially liable to be affected 

 — convulsions, spasms, coma, paralysis, etc., being common. 

 The symptoms due to disturbance or abolition of the functions 

 of secretory glands also constitute an important group, forming, 

 as they do, a striking analogy to what is found in the action of 

 various drugs. 



These tissue changes and symptoms are given only as illus- 

 trative examples, and the list might easily be greatly amplified. 

 The important fact, however, is that nearly all, if not quite all, 

 the changes found throughout the organs (without the actual pres- 

 ence of bacteria), and also the symptoms occurring 'in infective 

 diseases, can either be experim.entally reproduced by the injection 

 of bacterial poisons or have an analogy in the action of drugs. 



The Toxins produced by Bacteria. 



Early Work on Toxins. — We know that bacteria are capable 

 of giving rise to poisonous bodies within the animal body and 

 also in artificial media. As we shall see, we know comparatively 

 little- of the actual nature of such bodies, and therefore we apply 

 to them as a class the general term toxins. The necessity for 

 accounting for the general pathogenic effects of certain bacteria, 

 which in the corresponding diseases were not distributed through- 

 out the whole body, directed attention to the probable existence 

 of such toxins ; and the first to systematically study the produc- 

 tion of such poisonous bodies was Brieger. This observer 

 isolated from putrefying substances, and also from bacterial 



