396 COLLECTED STUDIES IN IMMUNITY 



we are coming to know more such blood poisons; the number of 

 different receptors which we can determine, therefore, continues 

 to increase. 



In this connection I should like to present the results which 

 Dr. Morgenroth and I have obtained in attempting to produce auto- 

 lysins by immunizing goats with blood from the same species instead 

 of blood from foreign species. In only one single instance were we 

 successful, i.e., in obtaining a solution of the animal's own blood- 

 cells. In all other cases we obtained merely an isolysin, which dis- 

 solved the blood-cells of other goats but not those of the goat immu- 

 nized. If the blood of a large number of goats is tested with a par- 

 ticular isolysin, it would be found that of some goats the blood is 

 highly susceptible, of others it is feebly susceptible, and of still others 

 the blood is not at all susceptible. In the case of the susceptible 

 bloods it can be shown that the isolysin consists of the arnboceptor 

 which is anchored, plus a complement of normal goat serum. In 

 course of time we have produced thirteen such isolytic sera, and found 

 to our surprise that they all differed from one another, i.e., that 

 they represented different isolysins. Thus the first serum dissolved 

 the blood-cells of A and B; a second serum those of C and D; a 

 third A and D, etc. By means of this one experiment we have, 

 therefore, come to know thirteen different lysins, to which, of course, 

 a similar number of receptors must correspond. It was fortunate 

 for us that in the blood-cells of an animal all the receptors were not 

 present, but only a part of the same, for it was only owing to this 

 fact that a separation of the different kinds was possible. 



It is worthy of note that many receptors may be present in the 

 blood-cells in relatively large amounts. If we designate as the single 

 lethal dose (L.D.) that amount of a certain arnboceptor which when 

 supplied with sufficient complement just suffices to completely dis- 

 solve a constant amount of blood, we can, by employing different 

 amounts of amboceptor solutions inactivated by heat, readily deter- 

 mine how many L.D. can be anchored by the amount of blood in 

 question. As a result of this it has been found that in some cases 

 only just the single L.D. is bound. More frequently the combining 

 power of the erythrocytes is much higher, so that two to ten and 

 even fifty times the L.D. is bound. In such cases, therefore, we 

 are dealing with a marked excess of these particular receptors. An 

 analogous case, by the way, has long been known as a result of 

 Wasseimann's experiment concerning the power of brain substance 



