The treatment of washed erythrocytes of the guinea-pig by a heated immune hemolytic serum derived from the rabbit, and of washed erythrocytes of the sheep by a similar serum derived from the goat, renders the erythrocytes more or less resistant to the subsequent action of tetanolysin.
If all the serum is removed from corpuscles treated in this manner, it can be determined that some of the protection is due to the agglutination of the cells. A certain amount of the protection afforded by agglutination is referable to the physical barrier which the agglutinated mass of cells offers to the uniform distribution and diffusion of the tetanolysin. It is probable that none of the protection obtained is due to the mere union of agglutinin or of hemolytic amboceptors with their respective cell-receptors; such union would appear to leave the tetanophile receptors still unoccupied. If a residuum of serum is left with the corpuscles which have been treated as indicated, the added protection which is acquired against the subsequent action of tetanolysin may reasonably be referred to antitoxin which is present in the residual serum. The possibility of the dissociation of a union between the tetanophile receptor and its antibody, occasioned by the dilution incident to washing away the serum, may not be entirely ignored, but has not been susceptible to determination. The same may be said of the possibility that tetanolysin, having a stronger affinity for the tetanophile receptor than has the antibody, is able to displace the latter from its union with the receptor.
Hence treating corpuscles with the immune serums does not allow one to determine the presence or absence of an antibody for the tetanophile receptor, the experiments being formulated on the supposition that such an antibody would unite with the tetanophile receptors and thereby prevent subsequent binding of tetanolysin.