158 THE TOXINES PRODUCED BY BACTERIA. 



They are certainly all uncrystallisable. They are soluble in 

 water and they are dialysable ; they are precipitated along 

 with proteids by concentrated alcohol. If they are proteids 

 they are either albumoses or allied to the albumoses. They 

 are relatively unstable, having their toxicity diminished or de- 

 stroyed by heat (the degree of heat which is destructive varies 

 much in different cases), light, and by certain chemical agents. 

 Regarding the toxines which are more intimately associated 

 with the bacterial cell we know much less, but it is probable 

 that their nature is similar, though some of them at least 

 are not so easily injured by heat, e.g., in the case of the 

 tubercle bacilli already mentioned. There is evidence in 

 the case of all toxines that the fatal dose for an animal varies 

 directly with the body weight. 



The comparison of the action of bacteria in the tissues 

 in the production of these toxines to what takes place in 

 the gastric digestion, has raised the question of the pos- 

 sibility of the elaboration by these bacteria of ferments by 

 which the process may be started. The problem of toxine 

 formation is thus still further complicated. Martin has 

 described toxic albumoses as occurring in all the diseases 

 he investigated, viz. anthrax, ulcerative endocarditis, 

 diphtheria, and tetanus. In each of these cases, therefore, 

 we would be led to suppose that ferments might be primarily 

 produced. Martin carries the analogy further, and sug- 

 gests that, just as by the secretion of ferments into the 

 intestine, the non-soluble albumins of the food are trans- 

 formed into the soluble albumoses and peptones which are 

 easily absorbed by the intestinal cells, so it is likely that 

 bacteria may excrete ferments which, acting on the albumins 

 in which they are living, may make the latter more available 

 for subsequent absorption as food. Looked at from the 

 side of the animal in or on which the bacteria are living, 

 these products of digestion are toxic, and it is evident that, 

 given a diffusible ferment, we may look on it as the primary 

 toxic agent which acts by producing secondary non-diastatic 

 poisons. Hitherto all attempts at the isolation of such 

 ferments in a pure condition have failed. 



