Infiuence of Temperature 113 



rabbits. Buchner and Gerct (16, vii. 1901) stimulated by the results 

 of Myers, treated rabbits with peptone prepared according to Kiihne. 

 Although the pe])tone possessed a considerable toxicity, they succeeded 

 in immunifying the rabbits, obtaining an " antiserum " which caused 

 a precipitum in peptone solutions, the precipitum being composed of 

 crystalline bodies or " globulites." On further investigation (8, viii. 1901) 

 they were surprised to find that these globulites consisted of barium 

 sulphate, the barium being derived from the peptone they had used. 

 When barium was excluded no reactions occurred. Briefly, they 

 obtained no antibody for peptone. Michaelis (9, X. 1902, p. 736) 

 repeated Myers' experiment, using Merck's egg-peptone, and " peptonum 

 siccum Riedel," both barium-free. He also obtained no antibodies for 

 these. On the other hand, I have noted elsewhere (under Phyto- 

 precipitins, Section VI.) that Kowarski has claimed to obtain precipitins 

 for plant albumose. Michaelis found but few of his rabbits to survive 

 the toxic effects of the peptones he injected. He concludes that egg- 

 peptone no longer possesses the side-chains which are present in the 

 egg-white molecule, giving rise in the latter case to the formation of 

 precipitins. The side-chains are destroyed through peptic digestion. 

 Obermayer and Pick (1902) also repeated Myers' experiment, treating 

 rabbits with Witte's peptone, finding that it produced little or no 

 precipitin when injected. The effects of peptic digestion upon pre- 

 cipitins and precipitable substances has been considered on p. 111. 



It would appear from the foregoing, that Myers and Schiltze are 

 mistaken with regard to the nature of the " precipitins " they found. 



I might add here that Klein (17, Vll. 1902) treated rabbits 

 intraperitoneally with injections of starch, glycogen (from fowl and 

 rabbit), grape-sugar, gum, and gelatin bub did not observe the formation 

 of precipitins. 



The Influence of Temperature upon the Reaction. 



The influence of temperature upon the precipitin reaction is well- 

 marked. Myers (14, vii. 1900) stated that it took place more rapidly 

 at 37° than at room temperature. This was subsequently confirmed by 

 Wassermann and Schutze (18, ii. 1901), Michaelis (9, x. 1902, p. 734), 

 and Stockis (v. 1901), the latter stating that 40 — 42° C. are most 

 favourable. Biondi (1902, p. 16) found the temperature to exert a 

 distinct influence. Linnossier and Lemoine (1902) found reactions to 

 occur at temperatures ranging from to 58° C, the amount of pre- 

 N. 8 



