CHAPTER XVIII. 



CYTOTOXINS. 



Following the discovery of immune hemolytic 

 serums it was a short step to experiments which 

 involved immunization with various other tissue 

 cells, and as a result of such work we are to-day 

 familiar with antiserums for almost every organ 

 of the body. 



Metchnikoff gave the name of cytotoxins to those 



Cytotoxin or . 6 _, >, i . 



cytoiysin. serums which aestroy cells other than bacteria 

 and erythrocytes ; the word cytoiysin is used syn- 

 onymously. Naturally a serum which destroys any 

 cell whatsoever is cytotoxic, but according to the 

 rather loose custom which prevails, we speak of 

 bacteriolysins, hemolysins and other cytolysins, in- 

 cluding among the latter serums which destroy 

 leucocytes, the cells of the liver, kidney and other 

 organs. 



Cytotoxins are of interest, not only because thev 



Theoretical > . J *- 



utility of are produced in accordance with the general 

 oxins * laws of anti-body formation, but they have, in ad- 

 dition, a certain theoretical and perhaps practical 

 importance. Immediately on their discovery the 

 possibility became manifest that they might be 

 utilized in the elucidation of certain physiologic 

 and pathologic problems. For example, by put- 

 ting the thyroid out of function through in- 

 jections of thyrotoxic serum it might be pos- 

 sible to confirm, or to prove incorrect, cer- 

 tain theories as to the role of the gland in 

 metabolism. Or, by the selective destruction of a 

 tissue, facts concerning its regenerative powers 



