438 TETANUS 



toxicity may still retain their power of producing immunity 

 against the potent toxin. Further, altogether apart from the 

 occurrence side by side in the crude toxin of strong and weak 

 poisons, it has been shown that such crude toxin contains toxic 

 substances of probably quite a different nature. Ehrlich has 

 shown that besides the predominant spasm-producing toxin 

 (called by him tetanospasmin), there often exists in crude toxin a 

 poison capable of producing the solution of certain red blood 

 corpuscles. This hsemolytic agent he calls tetanolysin. It does 

 not occur in all samples of crude tetanus toxin, nor is" it found 

 when a bouillon culture of the bacillus is filtered through 

 porcelain. To obtain it the fresh culture must be treated by 

 ammonium sulphate, as described in the method of obtaining 

 concentrated toxins (p. 200). This substance also has the 

 power of originating an antitoxin, so that certain antitetanic sera 

 can protect red blood corpuscles against its action. Madsen, 

 studying the interactions of this anti-tetanolysin with the 

 tetanolysin, has shown that phenomena can be demonstrated 

 similar to those noted by Ehrlich as occurring with diphtheria 

 toxin, and which the latter interpreted as indicating the presence 

 of degenerated toxins (toxoids) in the crude poison. With 

 tetanus as with diphtheria toxin the action of an acid is to 

 cause an apparent disappearance of toxicity, but if before a 

 certain time has elapsed the acid be neutralised by alkali, then a 

 degree of the toxicity returns. 



As with other members of the group, nothing is known of the 

 nature of tetanus toxin. Uschinsky has found that the tetanus 

 bacillus can produce its toxin when growing in a fluid containing 

 no proteid matter. The toxin may thus be formed independently 

 of the breaking up of the proteins on which the bacillus may be 

 living, though the latter no doubt has a digestive action on such 

 a protein as gelatin. There is, however, evidence that peptic 

 digestion and toxin formation are due to different vital processes 

 on the part of the tetanus bacillus. 



Whatever the nature of the toxin is, it is undoubtedly one 

 of the most powerful poisons known. Even with a probably 

 impure toxalbumin Brieger found that the fatal dose for a 

 mouse was "0005 of a milligramme. If the susceptibility of 

 man be the same as that of a mouse, the fatal dose for an average 

 adult would have been '23 of a milligramme. Animals differ 

 very much in their susceptibilities to the action of tetanus toxin. 

 According to v. Lingelsheim, if the minimal lethal dose per 

 gramme weight for a horse be taken as unity, that for the guinea- 

 pig would be 6 times the amount, the mouse 12, the goat 24, 



