( 339 ) 



each experiment six tubes were used, which contained consecutively ^) : 



N°. 1 : ' 'i„ c.C. complement, \'^ c.C. emulsion of streptococci, 



7j c.C. anti-streptococciis serum. 

 N". 2 : '/lo c.C. compl., \\ c.C. emulsion of str., 7, c.C. normal 

 horse-serum. 



N". 3: 7,0 c.C. compl., 7, c.C. physiological NaCl, 7, c.C. 

 anti-streptococcus serum. 



N". 4: 7io C.C. compl., '/, c.C. physiol. NaCI, 7, c.C. normal 

 horse-serum. 



N". 5 : \/,, c.C. physiol. NaCl, '/, c.C. emulsion of str., \', c.C. 

 anti-streptococcus serum. 



N°. 6: 7j„ c.C. physiol. NaCl, \/, c.C. emulsion of str., 7, cC. 

 normal horse-serum. 



The tubes are stirred and then remain at the same temperature as 

 the room. Afler 3 — 5 hours to each of the tubes is added 7io c.C. 

 of a mixture, composed of 2 c.C. of hemolytic serum and 1 c.C. 

 corpuscles of a rabbit, which were buspended in physiol. NaCl to 

 remove the adherent serum. Very soon, mostly within ten minutes 

 the tubes 2, 3 and 4 distinctly show the phenomenon of hemolyse; 

 which is naturally not brought about in tubes 5 and 6, the com- 

 plement being absent. The absence or presence of an amboceptor 

 in the examined serum is proved by the existence or non-existence 

 of the hemolyse in the first tube. 



It is necessary to repeat all these controll-experiments each time; 

 firstly, because some streptococci produce a hemolysin at their growth ; 

 secondly, because bacteria are able to combine the complement with- 

 out the aid of an amboceptor, although in a much smaller degree. 

 This may be observed very distinctly in vitro; for instance: in six 

 tubes successive dilutions of a culture of diphtheria bacilli were made; 

 to each tube V^„ c.C. of the complement was added. After three 

 hours 7io c.C. of a mixture, composed of 2 c.C. of hemolytic serum 

 (heated to 56' C.) and 1 c.C. corpuscles of a rabbit, suspended in 

 physiol. NaCl, was added. The result after half an hour was as 



1) As complement, the fresh blood-serum of a guinea-pig was used. The strep- 

 tococci, which were to be examined, were cultivated on Loeffler's coagulated 

 blood-serum and after 24 hours suspended in physiological NaGl to a homogeneous 

 emulsion. The antistreptococcus serum was heated in advance for one hour to 

 56° C, as well as the fresh normal horse-serum, used for controll, and the hemolj-tic 

 serum originating from guinea-pigs, which were treated 3 or 4 times with 5 c.C. 

 of defibrinated blood of rabbits. The physiological NaCI used, was always a solution 

 f 0,90/0. 



