428 



Dr. C. Bolton. On the 



[Jan. 25, 



In the test-tube containing 2 c.c. serum there was complete solution 

 of the corpuscles, and in the test-tube containing O'Ol c.c. serum there was a 

 trace of haemoglobin diffused in the clear fluid just above the deposited 

 corpuscles. 



From the experiment it was therefore found that 2 c.c. serum of this 

 rabbit would completely lake 1 c.c. of a 5-per-cent. suspension of guinea- 

 pig's corpuscles, and that a dilution of the serum of 1 in 400 was the greatest 

 which would produce any solution at all. 



It is not reliable to estimate the baeniolytic power solely by finding the 

 greatest dilution in which any solution will occur, or in other words the 

 vanishing point of haemolysis, because this vanishing point may occur in 

 higher dilutions in the case of a weaker serum than in the case of a stronger 

 serum. What is the exact reason for this phenomenon does not appear to 

 be at all clear. Gay (1) has, however, recently shown that in the case of high 

 dilutions the activity of the complement may be completely inhibited. 

 Bashford (2) has suggested that in the higher dilutions haemolysis is interfered 

 with by agglutination of the red corpuscles. 



The haemolytic power of most rabbits is fairly constant, but as they vary 

 somewhat within small limits, I examine the haemolytic power of each 

 rabbit's blood before injection. Care must be taken to use exactly the same 

 dilutions when the serum is subsequently tested, as the amount of dilution 

 affects the haemolytic power of the serum. 



Kceniolysis. — A few days after the first injection of guinea-pig's stomach 

 cells into the peritoneal cavity of the rabbit, the haemolytic power of the 

 rabbit's serum for guinea-pig's red corpuscles is found to have considerably 

 increased. In one case before injection 2 - 25 c.c. serum were necessary to 

 completely dissolve 1 c.c. of a 5-per-cent. suspension of corpuscles ; seven 

 days after the injection - 75 c.c. serum would dissolve the same amount 

 of corpuscles. 



This first increase of haemolysin is a true increase of the natural haemolysin 

 of the rabbit, because its action like that of the natural haemolysin is 

 destroyed by heat, and is not restored on adding normal guinea-pig's serum. 

 In other words, guinea-pig's complement will reactivate neither. 



At this early stage a slight amount of laking, varying in extent in different 

 cases, may be seen on reactivating the heated serum with guinea-pig's 

 complement, but this laking has never been to any degree extensive enough 

 to account for the increase of haemolysis. In the above experiment, 21 days 

 after the first injection, it was found that - 5 c.c. serum would completely 

 dissolve 1 c.c. suspension of corpuscles, but on heating 2*5 c.c. immune 

 serum to 55° C, and complementing with 0*25 c.c. guinea-pig's serum, only 



