TOXINES. 9 



any general method of importance that is universally applicable 

 to all toxines. 



On the other hand, we must not omit to mention briefly here 

 that toxine solutions do not invariably have a uniform strength. 

 This phenomenon manifests itself notably in the case of tetanus 

 poison. Apart from the fact that Nicolaier's bacillus produces 

 two totally different poisons viz., that which causes the charac- 

 teristic symptoms of tetanus, and tetanolysine (q.v.) very great 

 differences are also to be observed in individual solutions of the 

 poison as regards their specific activity. Although, as a general 

 rule, tetanus poison is considerably more toxic for guinea-pigs 

 than for rabbits, yet there are also some preparations of the 

 poison that are almost as deadly for rabbits as for guinea-pigs 



(TlZZONl). 



BEHEING has confirmed this statement with regard to Tizzoni's 

 poison, and has also found in the case of his own cultivations 

 that certain parts were, relatively, extremely poisonous to rabbits. 

 We must therefore conclude that tetanospasmine is not an indi- 

 vidual substance, but consists of different active constituents. 

 Similar phenomena have also been observed in the case of the 

 poisons of diphtheria. Over -neutralised poisons are known 

 which are absolutely without effect upon guinea-pigs, but are 

 still poisonous to rabbits. 1 



Assuming now that we have prepared cultivations of living 

 bacteria rich in toxines, it is necessary to treat them in such 

 a way as to eliminate the action of the living cells, so as to be 

 able to examine the poisons separately. For this purpose we can 

 either kill the bacteria, or attempt to remove them completely 

 from the poison. 



The first method, in which no attempt is made to remove the 

 dead cells, cannot, by itself, lead to any definite conclusion as to 

 the action of the poison, inasmuch as the dead bodies still possess 

 definite chemical and physiological properties, which must render 

 all deductions uncertain. Fortunately, this method, which was 

 formerly employed, can be dispensed with in the investigation of 

 true toxines, and, as a matter of fact, has fallen into complete 

 disuse. 



For it is- possible to separate true toxines from their parent 

 cells by filtration through filters impervious to bacteria. The chief 

 substances used for the filtration, in addition to infusorial earth 

 and chalk, are porcelain filters or Chamberland's candles. During 

 the filtration the greater portion of the toxine passes completely 

 into the filtrate, the residual cells retaining only as much viru- 

 1 For further particulars see Ehrlich, Munch, med. Woch., 1903, 33. 



