208 Tests with Precipitins 



Keactions 



o/ 

 In 



a 

 o 



25 



71 

 33 

 

 



n 







323 MAMMALIA 323 ... 



262 AVES 262 ... 



4 Eggs of Birds 3 1 



34 EEPTIHA 



7 Subclass Chelonia 2* 1 1 1 



3 Subclass Crocodilia 2t 1 



24 Subclass Sauria 24 



14 AMPHIBIA 14 ... 



22 PISCES 22 



T.CBUSTACEA 7 ... 



* Both dried, one from Central Africa. t One dried. 



The reactions of the first and second class will be seen to be confined 

 to bloods belonging to Chelonia, medium and faint reactions were 

 observed only amongst Crocodilia and avian egg-white dilutions. In my 

 paper of 20, I. 1902 I reported the first series of 250 bloods tested with 

 this antiserum, having found that the blood of Testudo ibera gave 

 a marked clouding, and of A. mississippiensis a faint clouding. These 

 tests are included in the above table. For further bloods tested see 

 the large tables at the end. 



(2) Tests with Anti-Ophidian Sera. 



In view of the extensive work involved in the production of other 

 antisera, I have been unable to produce anti-snake sera. Dr Graham- 

 Smith has been carrying on a series of tests with these, which he 

 reports upon in Section VIII. The observations of Lamb (16, vm. 1902) 

 on precipitins for cobra venom fall naturally under this head. 



Lamb treated rabbits subcutaneously for 4 5 months with injections 

 of pure unheated cobra venom, the injections being made at intervals of 

 about 10 days. At the time when precipitins appeared, the rabbit could 

 withstand four times the lethal dose of venom. Using Wright's sedi- 

 mentation tubes, he added 4 volumes of antiserum to 1 volume of 1 / 

 cobra venom solution, and obtained a reaction leading to a marked pre- 

 cipitum after 24 hours. An excess of antiserum added to weak venom 

 solutions gave the most precipitum. The precipitin was active for 

 those proteids in venom which are incoagulable by heat. Moderate 

 heating of the antiserum does not affect its action. A 0'2 /o solution of 

 cobra venom, heated to 75 C. for 30 minutes, after which the coagulated 

 proteids were removed by filtration, gave as much precipitum as unheated 



