14:0 THE LTSINS. 



blood of men, is difficult of explanation by this theory, unless we 

 assume that every individual is possessed of the agglutinins and 

 lysins which originated in that individual during fetal life by inter- 

 changeable immunization with the mother. This explanation pro- 

 vides for an existence of these substances more prolonged than seems 

 possible. (2) The origin and continued existence of agglutinins and 

 lysins in the body may be explained on the assumption that they are 

 due to the frequent absorption of bacterial substances, especially from 

 the intestines ; but the fetus has been found to be germ-free, and it 

 has been shown by Kraus and Clairmont that the serum of newly- 

 hatched pigeons often possesses very marked bacteriolytic action. 

 (3) There remains the possibility that normal agglutinins and lysins 

 may be due to self-immunization, resulting from the continued dis- 

 solution of- cells in the body. It is true that Ehrlich and Morgen- 

 roth did not succeed in producing an autolysin. Halban states that 

 there are present in normal blood not only idio-isoagglutinins and 

 idio-isolysins, but also idio-heteroagglutinins and idio-heterolysins. 

 The presence of the last-mentioned substances is indicated by the 

 property of normal blood of agglutinating and dissolving certain 

 foreign cells, also the blood corpuscles of other species of animals. 

 These substances can hardly be supposed to have their origin in self- 

 immunization. So long as we are unable by experimental means to 

 produce auto-agglutinins and auto-isolysins, it must be assumed that 

 the agglutinins and lysins of normal serum are inborn substances. 



Meltzer,^ having ascertained that the normal serum of the ox has 

 a marked hemolytic action on the erythrocjrtes of the rabbit, placed 

 this serum in the peritoneal cavities of rabbits, and, removing it afl«r 

 varied intervals, compared its hemolytic action on the corpuscles of 

 the rabbit with that manifested by the same serum before it was in- 

 troduced into the animal. These experiments led to the following 

 conclusion : " The normal hemolytic power of bullock's serum for 

 the red blood corpuscles of the rabbit disappears during a stay in the 

 peritoneal cavity of this animal ; and the disappearance is the greater 

 the longer the stay, and is independent of the absorption of the fluid ; 

 disappearance takes place even during the first fifteen minutes." 

 Further investigation showed that the disappearance of the hemo- 

 lysin was not due to the formation of an anti-hemolysin, and that the 

 hemolytic action of the ox serum was lost, but more slowly, when it 

 was introduced into the peritoneal cavity of a dead rabbit. From 

 this, Meltzer concluded that the disappearance of the hemolytic 

 power of the serum was due to the imbibition of one of the hemolytic 

 factors, and subsequent investigation showed that the factor absorbed 

 is the complement; however, he was not able to regenerate the 

 serum removed from the cavity by the addition of sera containing 

 various complements. Meltzer also ascertained that hemolytic serum 

 1 Medical Seeord, 60, 1901. 



