On Immunity with Special Rc-fcrmicc to Cell Life,. 431 



seven or eight minutes after the injection of the toxine, death occurred 

 from tetanus exactly as if no antitoxine had been given. Part of the 

 toxine, equal at least to the minimal lethal dose, must within this time 

 have disappeared from the blood, in which it would have been neu- 

 tralised, and passed over to the tissues, especially to the brain. The 

 experiments of Donitz were afterwards confirmed by an investigation 

 conducted in quite a different manner by Heymans, who showed that 

 a research animal from which, the blood had been removed imme- 

 diately after the injection of the minimal lethal dose of tetanus toxine, 

 and replaced by transfusion of fresh blood, succumbed from typical 

 tetanus. In this case, therefore, in that brief interval of time the 

 minimal lethal dose of toxine had passed through the walls of the 

 vessels and been taken up by the tissues. 



Eegarding the nature of the processes here concerned, a satisfactory 

 explanation was also afforded by the experiments of Donitz. It ad- 

 mitted of demonstration that the toxine held in the tissues could still 

 be withdrawn from them, if not the simple neutralising dose were 

 injected but larger quantities of the same. 



The quantity necessary was greater in proportion as the interval 

 elapsing after the injection of the toxine was longer. However, after 

 a definite period was exceeded, all possible doses of antitoxine, even 

 the very greatest, were impotent, notwithstanding that the animal at 

 the time of the injection of the antitoxine had not developed any 

 symptoms. Since a very great number of other chemical substances, 

 narcotics, alkaloids, and other neurotropic bodies, were not in a posi- 

 tion to withdraw the toxine once deposited in the central nervous 

 system, and as the property to do so was solely the characteristic of 

 the specific antitoxine, one was obliged to come to the conclusion that 

 the union between the toxine and the tissues, which could only be 

 overcome by means of a specific chemically-related antagonising agent, 

 must itself depend on a chemical combination. One was therefore 

 forced to accept the idea that the central nervous system, that is to 

 say certain ganglion cells in it, possessed atom groups resembling 

 those of the antitoxine, in having a maximum affinity for tetanus 

 poison. The predilection of the nervous system for tetanus toxine, 

 the rapid union of the toxine with the nervous tissue, the gradual 

 onset of the symptoms and their long duration could only be explained 

 by the existence of such toxophil groups. The statement of Donitz 

 that the tetanophile atom groups are in the guinea-pig essentially con- 

 fined to the central nervous system, whereas in the case of other 

 species, especially rabbits, these are also present in other organs, is one 

 of prominent importance. 



The beautiful experiments of Roux on intracerebral injection of 

 toxine have yielded absolute confirmation of the statement of Donitz. 

 Roux found in guinea-pigs that the same dose of tetanus toxine was 



