348 PROTEIN POISONS 



and egg-white intravenously in rabbits. The injections 

 were single and too large to be followed by marked rise, 

 and too small to result in marked depression of temperature. 

 However, that they noticed the ill effects of these injec- 

 tions is shown by the following quotation : " The poisonous 

 action of peptone was unknown to us at the time when the 

 experiments were made, but some of our rabbits died soon 

 after rather large injections of peptone. Moreover, un- 

 changed egg-white is not an indifferent substance, and it 

 has long been known that its direct introduction into the 

 blood may cause albuminuria and deep-seated changes 

 in the kidneys." 



Giirber and Hallauer 1 employed casein for the reason 

 that it may be distinguished from other proteins by the 

 action of rennin. Solutions of this protein were injected 

 intravenously into rabbits and the casein was detected in 

 the bile. Evidently the foreign protein was on its way to 

 the intestines where it might be properly digested. These 

 authors quite properly point out that because a protein 

 injected into the blood does not appear, or appears only 

 in part, in the urine, is no proof that it has been assimilated 

 in unchanged form by the tissues, because it may have 

 been carried to the intestine and there properly digested. 

 They also brought out another point, confirmed later 

 by our own work, that when the foreign protein diffuses 

 from the blood it carries with it some of the blood proteins. 

 This is true whether it is poured out into the intestine or 

 eliminated through the kidneys. 



The results obtained by Giirber and Hallauer have been 

 confirmed by Burckardt, 2 who injected hemielastin intra- 

 venously and found it in the wall of the small intestine. 

 He concluded that it had been brought to this locality 

 preparatory to its being properly digested and fitted for 

 assimilation. 



Friedemann and Isaac, 3 after extensive experimentation, 



1 Zeitsch. f. Biol , 1904, xlv, 372. 



2 Zeitsch. f. physiol. Chem., 1907, li, 506. 



3 Zeitsch. f. exp. Path. u. Ther., 1907, iv, 830. 



