XXXIX. THE RELATIONS EXISTING BETWEEN TOXIN 

 AND ANTITOXIN AND THE METHODS OF THEIR 

 STUDY. 1 



BY 



Prof. PAUL EHRLICH and DR. HANS SACHS. 



THE subject of toxins and antitoxins, although representing one 

 of the best studied domains of biology, is still the subject of lively 

 controversy. The difficulties which beset exact studies are obvious. 

 We are dealing with substances which, for the present at least, are 

 of unknown chemical constitution and which we are compelled to 

 employ in the form presented by the life activities of vegetable or 

 animal organisms, i.e., in an impure state and mixed with countless 

 other products of the living body. All attempts to isolate these 

 bodies and discover their chemical character encounter endless diffi- 

 culties, so that, if we consider their great significance in practical medi- 

 cine, it almost seems ironical for nature to offer these substances to 

 man in such an unstable and variable form. In spite of this, however, 

 scientific investigations have been able to obtain a deep insight into 

 the nature and mode of action of toxins and antitoxins; and since 

 chemical means could not be employed, it remained for the experi- 

 mental biologist to undertake these studies. In place ot chemical 

 analysis, therefore, we have the biological reaction, which in the case 

 of toxins is the characteristic toxic action, in the case of antitoxins 

 the property of specifically influencing or inhibiting this action. 



An event of considerable importance was the introduction of the 

 quantitative method of study by Ehrlich, a method which opened 

 the way for the present development of immunity studies. At the 

 same time Ehrlich's introduction of test-tube experiments (haemag- 

 glutination, haemolysis), by avoiding the individual fluctuations of 



1 Uber die Beziehungen zwischen Toxin und Antitoxin und die Wege ihrer 

 Erforschung, Leipzig, 1905, Gustav Fock. 



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