98 ANTIGENS AND ANTIBODIES 



i. e., amboceptors of the nature of the bacteriolysins, are formed not 

 only following the injection of bacteria, but also upon immunization 

 with other cellular elements, using the term immunization in the 

 more modern sense of the word, viz., to express the throwing into 

 action of the remarkable mechanism which results in the develop- 

 ment of what we term allergia, and of which the formation of 

 antibodies is the outcome (see above). 



Collectively we now term all those antibodies of amboceptor type 

 which are specifically directed against animal or vegetable cells, 

 cytolysins or cytotoxins, and we designate the individual members of 

 this order according to the cell against which their action is directed 

 (sc., according to the type of the corresponding antigen) and thus 

 distinguish between erythrocytolysins (hemolysins), leukocytolysins 

 (leuJcolysins) , epitheliolysins, spermatolysins, hepatolysins, neurolysins, 

 nephrolysins, etc. The bacteriolysins would thus merely represent a 

 species of cytolysins. 



The demonstration of some of these antibodies is a very simple 

 matter as their action in reference to certain cells leads to alterations 

 which are very manifest, while with others we rather surmise than 

 are able to prove that a specific effect has been produced. It should 

 be mentioned, moreover, that while we frequently speak of these 

 bodies as lysins, a true dissolution of the entire cell does not neces- 

 sarily take place, and it would really be more appropriate to use 

 the synonymous term cytotoxin. 



The first cytolysins of animal origin to be discovered were the 

 hemolysins (1898). After Belfanti and Cortone had first shown 

 that the blood of an animal of a given species A (horse), which had 

 been previously injected (immunized) with the blood of an animal 

 of a different species B (rabbit), becomes highly toxic for all represen- 

 tatives of species B, Bordet demonstrated that this result is accom- 

 panied by extensive destruction of the red cells in the animal B. He 

 also showed that the same effect upon the red cells could be produced 

 outside of the body. As the hemolyzing power of the serum A disap- 

 pears after heating to 50 to 60 C. for about thirty minutes, but is 

 restored upon the addition of fresh normal serum which is itself non- 

 hemolytic, Bordet concluded that the hemolytic effect of the immune 

 serum depended upon the joined action of two separate bodies, of 

 which one is present in every fresh normal serum and is thermo- 

 labile, while the other, thermostabile constituent, is formed only 



