BINDING OF H.EMOLYTIC AMBOCEPTORS. 597 



the quantity of amboceptor in solution is usually too minute to 

 be detected. Similar conditions in the solution have recently been 

 described for the hsemolytic substances of certain organ extracts. 

 These substances are only very slightly soluble hi salt solution. 

 Nevertheless, when susceptible blood-cells are present at the same 

 time, the substances are anchored by the cells, i.e., abstracted 

 from the solution, while a further minute quantity is given off to 

 the solution. In connection with the experiments made at that 

 time, 1 we called attention to the analogy existing between this 

 phenomenon and certain occurrences in dyeing. 



It was necessary, now, to determine how the complete ha3moly- 

 sin, i.e., amboceptor plus complement, would behave in an 

 experiment of this kind. The result was highly interesting, for 

 it was found that the ability of the amboceptor to pass from the 

 receptor of one blood corpuscle to that of another existed only 

 so long as the amboceptor had not also combined with comple- 

 ment. On adding immediately a suitable amount of complement 

 to mixtures of blood-cells laden with amboceptor and fresh blood- 

 cells, it will be found that only the former are dissolved, i.e., only 

 half of the mixture. Even when the complement is added after 

 10, 20, or 40 minutes, only part of the blood-cells is dissolved. It 

 is only when the complement is not added until after sixty minutes 

 have elapsed, i.e., after time has been given to permit the passage 

 of sufficient amboceptor, that complete haemolysis occurs. 



Twenty cc. of a 5% suspension of ox blood-cells freed from 

 serum are mixed with 0.048 cc. of the inactive immune serum =16 

 amboceptor units. The mixture is kept at 38 and frequently shaken, 

 after which the blood-cells are separated by centrifuging. The 

 blood-cells are washed three times with salt solution until the 

 wash water is entirely free from amboceptor. After making the 

 suspension up to the original volume, 1 cc. doses are mixed with 

 1 cc. doses of a fresh 5% suspension of ox blood-cells. The mixtures, 

 kept in a water-bath at 40 each, received 0.2 cc. doses of guinea-pig 

 serum at different intervals, namely, at once, and after 10, 20, 

 40, and 60 minutes. In order to produce the maximum ha3molytic 

 effect, all the tubes were kept in the water-bath for three hours. 

 At the end of that time, half of the blood-cells, corresponding to 



1 Korschun and Morgenroth, Berliner klin. Wochenschrift, No. 37, 1902. 

 This volume, page 267. 



