174 COCA. 



stances sought M-erc (•omi)lement, ha^molytie immune-body, and the 

 lisemagghitinins, all of these being readily detected both qualitatively 

 and quantitatively. 



The method of preparing the fibrin extract wa^ identical with that 

 adopted by Bergel with the exception that sometimes the quantity of 

 salt solution used for the extraction was less than the amount of blood 

 yielding the fibrin. 



Complcnient in fihrin. — The entire amount of fibrin obtained from 15 

 cubic centimeters of guinea pig's blood by whipping, after having been 

 thoroughly washed in physiological salt solution and finely cut up with 

 scissoi'S, was suspended in 15 cubic centimeters of the salt soluiJon 

 and left for thirty hours at 15° ; the serum from the same animal was 

 kept at the same temperature. 



The relative amount of hfemolytic complement in both senini and 

 fibrin-extract was then determined in the usual manner : 



Series of tubes A: 



In all tubes 1 cubic centimeter 5 per cent sensitized bullock's blood corpuscles. 

 Diminishing quantities of fibrin-extract, 2.4 cubic centimeters, 1.6 cubic centi- 

 meters, 0.8 cubic centimeter, etc. 

 Series of tubes B: 



In all tubes 1 cubic centimeter 5 per cent sensitized bullock's blood corpuscles. 

 Diminishing quantities of guinea pig's serum, 1/20 cubic centimeter, 1/40 

 cubic centimeter, 1/80 cubic centimeter, etc. 



At the end of the usual period of observation no trace of' haemolysis 

 was to be found in Series A, whereas in Series B 1/20, 1/40, and 1/80 

 cubic centimeter of serum had produced complete solution, 1/160 cubic 

 centimeter moderate solution. 



The amount of available complement in the fibrin from 2.4 cubic 

 centimeters of guinea pig's blood is, therefore, less than that present in 

 1/160 cubic centimeter of the blood-serum of the same animal. 



Hcemolytic immune-body in fihrin. — Babbit No. 21 was given in the 

 ear vein 5 cubic centimeters of washed bullock's blood corpuscles and two 

 and one-half weeks later a similar injection of 10 cubic centimeters. 

 i*]igbt days after the second injection the animal was killed and the fibrin 

 from 50 cubic centimeters of its blood used for the following experiment. 

 The fibrin-extract was prepared as before, only 10 cubic centimeters of 

 salt solution being used for the extraction. 



Series of tubes A: 



Tn each tube 1 cubic centimeter 5 per cent bullock's blood corpuscles. 

 Diminishing quantities of fibrin extract, 4/10, 2/10 cubic centimeter, etc., to 

 1/100 cubic centimeter. 

 Series of tubes B : 



In each tube 1 cubic centimeter 5 per cent bullock's blood corpuscles. 

 Diminishing quantities of serum, 1/100, 1/320 cubic centimeter, etc., to 

 1/1280 cubic centimeter. 



