THE RECEPTOR APPARATUS OF THE RED BLOOD-CELLS. 391 



cells; for the present at least their chemical nature is unknown. Into 

 this class, to mention only the simplest types, belong the following: 



1. Poisonous phytalbumoses: ricin, abrin, crotin, phallin; 



2. Bacterial secretions; tetanolysin (Ehrlich, Madsen), staphylo- 

 toxin (van de Velde, M. Neisser, and F. Wechsberg), pyocyaneous 

 poison (Bulloch), streptococcus poison (v. Lingelsheim), cholera 

 poison, and probably many others. 



3. Poisonous animal secretions, especially the various snake 

 venoms. 



The majority of these substances, especially all of the bacterial 

 products, produce ordinary haemolysis. In contrast to this, as 

 Kobert has shown, abrin and ricin cause a rapid clumping of the 

 erythrocytes, a process which is analogous to the agglutinative phe- 

 nomena studied by Gruber, Durham, and Widal. However, in the 

 case of the poisonous phytalbumoses we cannot assume that there 

 is an essential difference between haemolysis and agglutinatin, be- 

 cause one of them, crotin, has been shown by Elfstrand to exert a 

 pure agglutining action on certain species of blood (sheep, pig, ox) 

 and a pure solvent action on others (rabbit). 1 



Of especial importance, however, is the fact that all these poisons 

 on being introduced into the animal body produce specific antitox- 

 ins (antiricin, antiabrin (Ehrlich); anticrotin (Morgenroth) ; anti- 

 tetanolysin (Madsen); antileucoeidin (van de Velde). In view of 

 what we have already discussed this fact alone is sufficient to ascribe 

 to these substances the possession of a haptophore group through 

 which they exert their toxicity. Furthermore, just like the true 

 toxins, they possess a second group which is the cause of the toxic 

 action. As Madsen has shown in the case of tetanolysin, and M. Neisser 

 and F. Wechsberg for staphylolysin, it is possible to change these 

 poisons into modifications which have more or less completely lost 

 their toxicity but which preserve unchanged the properties dependent 

 on the possession of the haptophore group (affinity for the anti- 

 body, production of immunity). These modifications, first recognized 



1 Even ricin, which is apparently purely agglutinating, exerts an action on 

 the discoplasma which causes haemolysis. In the ordinary technique of the 

 experiment this action is obscured by the fact that in the agglutinated masses 

 the conditions are very unfavorable for diffusion. If these conditions are 

 made more favorable by breaking up the clumps by shaking, one can easily 

 observe the escape of the haemoglobin. 



