226 IMMUNOLOGY 



necessary to have a precipitating serum that is clear, of high 

 potency, and that is specific. Satisfactory sera are best prepared 

 from rabbits or roosters. 



Inoculation of Anim.\i.s. — It seems that any of several methods 

 of immunization yields satisfactory results. Since different indi- 

 viduals of the same species vary in their capacities to produce 

 antibody, one should inoculate several rabbits in order to be 

 certain of obtaining a satisfactory antiserum regardless oC the 

 particular technique adopted. 



Inoculation of Animals According to Kolmer. — Kolmer 

 recommends that 0.5 c.c. of the antigen be injected intravenously 

 eveiy day for three weeks and a trial titration made ten days after 

 the last injection. If the titer is low he suggests that 5.0 c.c. be 

 given intraperitoneally and twenty-four hours later another series 

 of intravenous injections be started. 



Inoculation of Animals According to Dean. — Dean (1931) 

 recommends that two series of injections be given. Each series con- 

 sists of six to eight injections, each of 2 c.c. of the antigen at five 

 day intervals. The first few injections are given intravenously, 

 and the remainder intraperitoneally. After a re.st of three to six 

 months the second series is given. 



Methods Used in This Laboratory. — Various methods are used 

 in this laboratory. One is essentially that recommended by Kol- 

 mer, another is quite similar to the procedure followed by Nuttall. 

 One or two c.c. of the antigen (serum undiluted, egg white 50 

 per cent or crystalline egg albumen 1 to 5 per cent) is injected 

 into the marginal ear vein of a rabbit. This is followed three 

 to six days later by either another intravenous injection of the 

 same amount or by an intraperitoneal injection of 4 or 5 c.c. of 

 the antigen. A third, fourth and frequently a fifth injection is 

 given intraperitoneally at 3 to 6 day intervals and the animals 

 bled for antibody titration 7 to 10 days after the last injection. 

 Normal (0.85 per cent) saline is used as a diluent. 



Where a rooster is used for precipitin production, one injection 

 of 20 c.c. of whole blood or other antigenic material is given intra- 

 peritoneally. After ten or twelve days blood is removed from the 

 heart and titrated for precipitin content. Hektoen recommends 



