TOXINES. 1 3 



and to whose properties they offer the closest analogies in their 

 reactions and activity. 



These analogies stand out in the sharpest relief, when we 

 compare the influence of external factors on bacterial toxines 

 with their effect upon ferments. There is the closest corre- 

 spondence in almost every particular. 



A special characteristic of toxines is their extreme sensitive- 

 ness to the action of heat. In their normal solutions they soon 

 perish at temperatures above 50 C. ; at 80 C. their activity 

 is at once destroyed, and even at 45 C. they are slowly 

 decomposed. Individual ferments differ but little in this 

 respect. On the other hand, they offer great resistance to the 

 action of dry heat. Solid preparations can be heated to over 

 100 C. without suffering injury ; but even these appear to be 

 destroyed by a temperature of 150 C. 



It is interesting to note that in liquids devoid of water, such 

 as amyl alcohol, they can also be heated far above 80 C., and that 

 many salts, such as, e.g., anhydrous sodium sulphate, increase 

 their resistance to the acfcion of heat (BuCHNEE 1 ). Low tem- 

 peratures check their activity, but do not otherwise injure them. 



They dialyse to a slight extent through parchment, but not 

 through collodion (RoDET and GUECHOFF 2 ), and through animal 

 membranes, such as those of the oesophagus, bladder, large intes- 

 tine, and especially the small intestine (CHASSIN and Moussu 3 ). 



In all these respects they behave exactly like enzymes. 



Toxines are more sensitive than enzymes to the action of light. 

 Diphtheria or tetanus poison in aqueous solution is very rapidly 

 destroyed by both sunlight and diffused daylight (tetanus poison 

 within forty-eight hours according to KiTASATO 4 ). Light is 

 without action upon them when they are in the dry condition, 

 or suspended in liquids devoid of water. 



An electric current can also be injurious to toxines, though 

 only when continuous, for alternating currents of high tension 

 are quite harmless to tetanus poison (MARMIER 5 ). Even when 

 merely allowed to stand in solution in the dark, with every 

 precaution, the poisons gradually become weaker, being decom- 

 posed, at any rate, in the case of diphtheria and some other 



J Buchner, " Bakteriengifte und Gegengifte," Munch, med. Woch., 1893, 

 449. 



2 Rodet and Gue"choff, Soc. Biol., Hi., 965, 1900. 



3 Chassin and Moussu, "Influence de la dialyse, &c.," ibid., lii., 694, 

 1900. 



4 Kitasato, "Exper. Unt. iib. d. Tet. Gift.," Zeit. f. Hyg., x. 287, 1891. 



5 Marmier, " Les toxines et 1'e'lectricite', " Ann. Past., x., 469, 1896. 



