294 Scientific Proceedings (116). 



Three antisera were employed: (i) Antityphoid (rabbit) 

 serum, (2) antiabortion (ox) serum and (3) antimallei (rabbit) 

 serum. The antigens were bacillary suspensions of the specific 

 organisms titrated in accordance with standard technique. The 

 complement fixation tests were carried out in each case with un- 

 heated serum and the same immune serum subjected to different 

 temperatures up to 85 degrees C, for varying intervals. 



It was found after subjecting these sera to a water-bath tem- 

 perature of 65 degrees C. (the thermal destructive temperature 

 of syphilitic sera) for 1 hour, that the antibodies remained in 

 tact. Higher temperatures showed varying degrees of anti- 

 body destruction depending particularly on the time of exposure. 

 One hour heating at 70 degrees C. caused between 20 and 60 per 

 cent, of antibody destruction. Thirty minutes exposure at 75 

 degrees C. caused between 80 to 90 per cent, of destruction. 

 Fifteen minutes at 80 degrees C. destroyed the antibodies com- 

 pletely. 



151 (1733) 



On the persistence of complement fixing antibodies in the serum 

 of rabbits immunized with purified proteins. 



By R. L. KAHN. 



[From the Bureau of Laboratories, Michigan Department 

 of Health, Lansing, Mich.] 



This report is based on two experiments: Rabbit A was im- 

 munized intravenously with edestin and Rabbit B, intraperitone- 

 al^ with phaseolin. Rabbit A received the first injection of pro- 

 tein November 15, 1920, and the last, eight days later. The 

 quantities injected were 50, 75, 100, 125 and 150 mgm. — a total 

 of 0.5 gm. Rabbit B received its injections between December 28, 

 1920, and January 5, 192 1 ; the quantities were 100, 150, 200, 250 

 and 300 mgm. of protein — a total of 1 gm. The sera of these 

 rabbits were examined from time to time for the presence of 

 specific complement fixing antibodies, the last examination having 

 been made on May 5, 192 1. The results showed a gradual de- 



