THE TECHNIQUE OF SERUM REACTIONS 25S 



traperitoneally or intravenously, at intervals of from five to six days, 

 the dosage and mode of administration being adapted in each case to 

 the pathogenic properties of the microorganisms in question. It has 

 been asserted by Myers ' that when pepton-broth cultures are used for 

 immunization a specific precipitin for pepton may be formed which by 

 giving a precipitate with a culture filtrate containing pepton may lead 

 to error. This observation could not be confiimed by Norris.^ 



The immunized animals should be bled about seven to twelve days 

 after the last injection of bacteria. 



Specific precipitating antisera against proteid solutions are prepared 

 by methods analogous to those employed for the production of anti- 

 bacterial sera. A variety of methods have been described. The sera 

 or proteid solutions used should be sterile. This may be accomplished 

 by filtration through small porcelain filters. The injections into animals 

 may be made subcutaneously, intraperitoneally, or intravenously. The 

 subcutaneous route has no advantages unless the substances to be used 

 are contaminated. 



Nuttall advises the use of rabbits. The animals should be weighed 

 from time to time, and if considerable loss of weight ensues during im- 

 munization, the intervals between injections should be increased. 

 Dosage should be carefully graded, beginning, in the case of an animal 

 serum, for instance, with 2 c.c. and increasing gradually through 3, 5, 

 and 8 c.c. to possibly 15 c.c. at the last injection. A single injection of 

 a large quantity has occasionally yielded a precipitating serum of con- 

 siderable strength,' but this method is not usually successful. Injec- 

 tions are made at intervals of from five to seven days. Seven to twelve 

 days after the last injection the animals may be bled, and a preliminary 

 test made to ascertain the precipitating value of the serum. If this is 

 insufficient for the desired purposes, more injections may be made before 

 the animal is finally bled. Bleeding should be done seven to twelve 

 days after the last injection. Such sera may be preserved by seahng in 

 glass bulbs and keeping in the dark and at a low temperature. If a 

 preservative is to be added, Nuttall recommends chloroform, but dis- 

 approves of the phenols, because of occasional turbidity produced by 

 these. 



The precipitating antisera used for the tests should be absolutely 



' Myers, Lancet, ii, 1900. 



' N orris, loc. cit. 



« Michaelis, Deut. med. Woch., 1902, 



