214 BACTERIA PATHOGENIC TO MAN 



the greatest affinity for antitoxin, while the epitoxoid has the least. 

 The toxins are divided into an alpha and a beta portion, depending on 

 the ease with which they are changed into toxoids. All of these sub- 

 stances unite with tissue cells and with antitoxin through the agency 

 of a haptophore group, while the toxicity depends on the presence of 

 a toxophore group in the toxin or toxon molecule. 



Bordet and others refuse to accept these complicated conceptions 

 of Ehrlich and the whole matter is at the present time under active 

 discussion. Thus the existence or non-existence of toxons has excited 

 a great deal of discussion among investigators. The great Swedish 

 chemist, Arrhenius, has recently given much attention to toxins and is 

 applying the principles of physical chemistry to the study of toxins 

 and antitoxins. It is a well-known fact that some chemical substances 

 when in solution have the power of breaking up into their constituent 

 parts; thus sodium chloride breaks up in part into sodium and chlorine, 

 as sodium or chlorine ions or electrolytes. The dissociated sodium and 

 chlorine may then enter into combination with any other suitable sub- 

 stance which may be present. Arrhenius holds that this is the case 

 with the toxin-antitoxin molecule, that it may to a certain extent again 

 break up into separate toxin and antitoxin. He believes that this dis- 

 sociated toxin is the substance which Ehrlich has been calling toxon. 

 Madsen, who formerly had done much work with toxons, has now 

 joined with Arrhenius in support of the dissociation theory. In spite of 

 their reasoning Ehrlich and his followers continue to uphold the toxon 

 as an independent toxic substance. Recent investigations throw doubt 

 on both explanations as being at all final. 



Standardizing of Antitoxin Testing. Ehrlich has contributed greatly 

 to uniformity in results in testing antitoxin by calling attention to 

 the necessity of selecting a suitable toxin and by employing and 

 distributing an antitoxin as a standard to test toxins by. In this way 

 smaller testing stations can make their results correspond with those of 

 the central station. The United States Marine Hospital laboratories 

 have recently begun to distribute to laboratories in the United States 

 an equally carefully standardized serum. 



In spite of the great variations in the neutralizing value of a fatal 

 dose in different toxins we do not believe that even before adopting the 

 use of a standard serum there has been any such great difference in 

 the toxins used by the different stations for testing purposes. Most 

 laboratories have taken the culture fluid at about the time of its greatest 

 toxicity, and the neutralizing value of a fatal dose of this toxin would 

 seldom vary more than 10 per cent, above or below the standard now 

 adopted in Germany by the government testing station. 



Where error has been made it has usually been by taking too old 

 culture fluids, which would cause the antitoxin strength of samples 

 tested to be estimated below and not above its real value. Culture 8, 

 which is used not only by the New York Board of Health Laboratory, 

 but by many other laboratories in the United States and Europe, for- 

 tunately produces on the sixth to eighth day the time at which the 



