HOST RESPONSE TO ANTIGENIC ACTION 453 



preparations of Type I antipneumococcic serum, obtained from 

 rabbits, sensitized the albino guinea pig so that an injection of 0.1 

 cubic centimeter of a 1 to 10,000 dilution of Type I polysaccha- 

 ride into the skin of the ear elicited a positive reaction. However, 

 when antipneumococcic serum from the horse was employed, the 

 same dose of antigen gave variable results, although the injection 

 of twice the amount evoked positive reactions. Experiments on the 

 distribution of immune horse serum as compared with that of rab- 

 bit serum in the circulation and organs of passively immunized 

 guinea pigs failed to disclose any explanation for the differences 

 in the sensitizing action of the two serums. 



Brown 155 " 6 reported similar observations on the ability of anti- 

 pneumococcic rabbit serum to sensitize passively the guinea pig to 

 the specific carbohydrate of Type I Pneumococcus. Brown found 

 that the minimal amount of antiserum necessary to sensitize the 

 guinea pig so that fatal shock followed the injection into the 

 heart of the soluble specific substance was always greater than 

 the quantity of serum required to sensitize to the cellular carbo- 

 hydrate of Wadsworth. However, the minimal amount of each of 

 the specific carbohydrates which induced fatal shock in guinea 

 pigs previously sensitized by the injection of one cubic centimeter 

 of immune rabbit serum was approximately the same. 



The protective or inhibitory action of artificial, conjugated 

 sugar-proteins on the anaphylactic reaction of guinea pigs pas- 

 sively sensitized with antipneumococcic rabbit serum, as reported 

 by Tillett, Avery, and Goebel, 1407 was confirmed by Brown 156 in the 

 case of the soluble specific substance and of the cellular carbo- 

 hydrate. A subcutaneous injection of a suitable dose of soluble 

 specific substance of Type I Pneumococcus given to guinea pigs 

 twenty-four hours after passive sensitization with Type I anti- 

 pneumococcic rabbit serum completely desensitized the animals 

 to intracardial injection twenty-four hours later of capsular poly- 

 saccharide, but not to a similar injection of cellular carbohydrate. 

 The latter substance, however, completely desensitized the guinea 



