THE MODE OF ACTION OF COBRA VENOM. 



297 



As a matter of fact we have succeeded in a large number of cases 

 in causing the solution of such cells by the addition of laky solutions 

 of endocomplement. 1 The amount of endocomplement contained in 

 blood-cells varies; that of human and guinea-pig blood appears 

 to be the highest and also fairly constant. 



The following table shows the combinations in which, according 

 to our experiments, cobra poison causes solution ( + ) of blood-cells 

 which are not dissolved by cobra poison alone (see Table IV). 



TABLE IV. 



It is in place here to mention another fact. The deflection of the 

 endocomplement by large quantities of poison described in the case 

 of blood-cells vulnerable to cobra poison succeeds equally well if 

 the experiment is made with blood-cells insensitive to cobra poison 

 alone (ox blood) and if dissolved endocomplements (guinea-pig) are 

 used for activation. There is no doubt therefore that the blood-cells 

 themselves contain complement-like substances, endocomplements. 



So far as the behavior of these endocomplements toward thermic 

 influences is concerned, they are seen to be somewhat more resistant 

 in general than are the complements contained in the serum, for it 

 requires half an hour's heating to 62 C. to inactivate them (see Table 

 V). In the light of our present knowledge, however, we probably 

 cannot deny the complement character of these substances merely 



1 As a rule these endocomplement solutions were prepared by twice washing 

 and centrifuging a certain quantity of full blood, and then filling the sediment 

 up to a certain volume. Either the original volume or a greater or less dilu- 

 tion was made up depending on circumstances. They were then salted to 

 contain 0.85% NaCl. We have designated these dilutions as J, $, -fa, etc., endo- 

 complement. 



2 Even in these cases we noticed an activation with certain specimens of 

 blood. 



