114 ACTION OF LEUCOCYTES ON TOXINS 



same substance when shielded from the leucocytes by being 

 enclosed in permeable bags before being placed in the peritoneum ; 

 in this case the animal died, the arsenic doubtless becoming 

 dissolved, and thus escaping the action of the leucocytes. He 

 found also that substances which diminished the number of the 

 leucocytes in the peritoneal fluid aided the action of the arsenic, 

 whilst those which caused a leucocytosis diminished it. He found 

 similar facts with relation to the action of a soluble salt of arsenic, 

 and showed that in animals which had been immunized to that 

 substance the arsenic is especially taken up by the leucocytes. 

 There can be no doubt, therefore, that the leucocytes play a role 

 of the utmost importance in the defence of the body against the 

 ordinary poisons. 



All things being considered, we may deduce that antitoxin is 

 formed from any cell with which the toxin can combine, provided 

 that that cell is not too profoundly injured in the process, and 

 may attribute to the leucocytes an important, though not an 

 exclusive, role in this process. It is hardly necessary to say that 

 this does not disprove the side-chain theory ; we must regard the 

 leucocytes as being cells which are specially told off for the 

 defence of the organism against infections and intoxications. 

 They are, in consequence, specially immune to the action of 

 toxins, being able to resist amounts which are injurious to the 

 more highly organized tissues ; that this is the case is proved 

 by their invasion and persistence in a living state in areas in 

 which the tissues are profoundly injured by a toxin. It is not 

 difficult to believe that these resistant cells, which have a special 

 predilection for intoxicated areas in which antitoxin is especially 

 required, should be the source of that substance. We have, then, 

 only to regard them as possessing suitable haptophore groups and 

 as being relatively insusceptible to the toxophore groups both of 

 which are inherently probable to see that they fulfil in a special 

 way the criteria which the side-chain theory demands for cells 

 which are to produce antitoxin when exposed to the action of 

 toxins. 



