410 Mr. G. Dean. Enquiry into the Nature of the [Apr. 23 y 



obtained by heated horse serum under the same conditions, i.e., a loss has 

 occurred comparable to that produced by heating to 60° C. for 20 minutes. 



Table V. — Eesults of Experiments with Anti- complement (Horse) Serum 

 obtained from Babbit, together with Control Eesults. 



Number of 

 experiment. 



Fresh normal serum of horse, 



+ 



Serum of horse heated (60° for 20 mins.), 



+ 



A. B. 



XT , ,, .,, i Anti-complement 

 Normal rabbit s i £ r ,,.. 

 tt j. j i. serum ot rabbit, 

 serum. Heated to tt j. i ± Crt o n 

 nnp n j? oa • Heated to 60 C. 

 60 C. for 20 nuns. , ort . 



for 20 nuns. 



C. 



Normal serum of 

 rabbit. Heated to 

 60° C. for 20 mins. 



D. 



Anti-complement 



serum of rabbit. 



Heated to 60° C. 



for 20 mins. 



1 

 2 

 3 



4 

 5 

 6 



7 



Total 



Mean of 

 experiments 



17 5 

 10 7 

 8-3 

 8-4 

 6*3 

 7 1 

 6-0 



7 5 

 3 5 

 2 1 

 1-1 

 0-6 

 4'4 

 2 5 



4-1 

 1-2 

 2 6 

 1-1 



1-3 



1-4 

 1-0 



5-5 

 3-4 

 0-8 

 3 2 

 0-2 

 3'0 

 1-1 



64-3 



21-7 



12-7 



17-2 



} 91 



3-1 



1-8 



2-4 



The serum of the horse, after having been heated for 20 minutes to 60° G. r 

 still shows some sensitising power, even when tested by Wright and 

 Douglas' method. Several comparative tests by my assistants and myself, 

 where a large number of leucocytes had been counted, show that heated 

 normal horse serum, compared with normal salt solution, gave average counts 

 in the ratio of about 4:1. 



Action of Anti- Complement Serum in Complemented Mixtures. 



The following experiments with staphylococci may be reported in full 

 as the type of such experiments. The usual opsonic technique was 

 employed, the constituent parts of the mixture introduced into the tubes 

 being as follows (see table, p. 411). 



A comparison of 1 and 4 shows that, by the action of anti-complement 

 serum, the phagocytic average has been reduced from 15*1 to 2'4. 



Similar experiments with the dysentery immune serum of the horse com- 

 plemented with normal human serum showed, as the result of the action of 

 the anti-complement serum, a reduction in the phagocytic index in one 

 experiment from 7*5 to 1*3, in another from 5'9 to 1*7. In this case human 

 anti-complement serum and horse leucocytes were employed. 



