ON THE ANTITOXINS OF DIPHTHERIA. 197 



diphtherise produces indol and oxidises ammonia to nitrite 

 so that a characteristic red colour may be obtained by the 

 addition of acid to cultures three weeks old (16). Both 

 inside and outside the body toxins are developed, and these 

 appear in a bacterial-free filtrate. The toxins on injection will 

 produce diphtheria equally with the introduction of virulent 

 bacilli, and since the inoculated micro-organisms multiply 

 at the seat of the original lesion, and do not wander at all, 

 or only to a slight degree with the tissues of the body (17), 

 the bacillus belongs to that group of toxic micro-organisms 

 which also includes the micro-organisms of tetanus and 

 possibly of typhoid fever. From the tissues of those who 

 have succumbed to diphtheria, as Martin (18) and others 

 have shown, toxic substances which appear to be proteids 

 may be recovered. The toxins of a bacterial filtrate and 

 those separated from the dead body appear to be different 

 in many respects. The former are considered to be fer- 

 ments or enzymes, which are probably the result of the 

 exchange of material effected by the bacillus, though 

 according to Buchner they are disintegration products, 

 or proteines derived from the protoplasm of the micro- 

 organism. Notwithstanding most elaborate researches 

 into the chemical and physical nature of the toxins or 

 toxin of Bacillus diphtherise, and repeated attempts to 

 isolate them in a state of purity, little is known beyond the 

 specific effects which follow the injection of these substances 

 into animals. 



If it can be affirmed that a disease is caused by the 

 invasion of specific microbes, or their products, attempts to 

 destroy these would be a strictly scientific procedure ; in 

 other words, attempts to disinfect the living body. Quinine, 

 salts of mercury, iodine or salicylic acid are powerful dis- 

 infectants, and also valuable drugs frequently employed in 

 the treatment of diseases produced by the spread of bacteria 

 in the body. In order to accomplish a disinfection of the 

 living body numerous experiments have been made, but the 

 results were unfavourable, until Behrino and his colleagues 

 Knorr and Boer announced that this was possible in certain 

 diseases, such as anthrax, tetanus and diphtheria ; tri- 



