202 SCIENCE PROGRESS. 



is still more remarkable. Diphtheria toxin is obtained 

 by growth of the bacillus on serum or nutrient media, in 

 which serum-albumin or serum-globulin is the chief con- 

 stituent. Toxins are produced in the first two fluids, but 

 not in the last, since the bacillus thrives very badly on 

 serum-globulin, and produces no toxin at all. By elec- 

 trolysis of the filtrate of virulent cultures, the existing 

 toxins disappear, and the fluid becomes powerfully anti- 

 toxic. That toxins are destroyed by a current of 500 

 milliamperes for two hours is a fact beyond all doubt, and 

 this destructive effect also is exhibited on enzymes, such as 

 pepsin or trypsin (30). The introduction of this artificial 

 antitoxic fluid is curative for rabbits which have received a 

 lethal dose of toxin some hours previously, and this effect 

 resembles that seen when ordinary antitoxic serum is em- 

 ployed. The relations which may exist between diphtheria 

 toxin and antitoxin are supported by the evidence adduced 

 that the more toxic the toxin, the more antitoxic the anti- 

 toxin. The latter is not destroyed by boiling, and is an 

 effectual therapeutic remedy. These experiments have 

 only recently been published, and they certainly do support 

 the contention of many bacteriologists that antitoxins which 

 do not exist in naturally immune animals such as the 

 rat until toxins have been introduced into the body, are 

 derived from the toxin itself (31). Moreover, the passage 

 of a current through living cells which contain an ante- 

 cedent stage of such a ferment as trypsin can effect a 

 production of the ferment itself. Smirnow's work at any 

 rate marks a new method of research on the nature of 

 antitoxins, though the nature of these bodies still remains 

 a mystery. 



Researches on the toxic properties of abrin, ricin and 

 robin made by Ehrlich proved that antitoxic bodies leave 

 the organism in the milk. The same holds good when 

 diphtheria toxin is used in small doses, gradually increas- 

 ing in amount so as to produce a high grade of immunity 

 in goats (32). The therapeutic value of milk is dependent 

 upon the amount of antitoxins present, and contrasted with 

 an equal quantity of blood the ratio is 1 : 20. Although milk 



