56 PROTEIN DIGESTION IN THE INTESTINE 



The numerous positive findings 23 of albumoses in the 

 blood of animals during digestion are contradicted by a 

 series of other studies in which the higher molecular prod- 

 ucts of protein dissociation were entirely missed in the 

 blood at the height of digestion. 24 A recent controversy be- 

 tween E. Abderhalden and E. Freund in reference to this 

 discrepancy brings out distinctly the difficulties involved 

 both in method and in the significance of the results of ex- 

 perimentation. 25 It is extremely difficult to coagulate fully 

 the entire mass of haemic proteins; and small protein 

 residua which have escaped coagulation may very easily 

 come to be looked upon as " albumoses. " Then, too, as dis- 

 cussed in the previous volume of these lectures (Chemistry 

 of the Tissues, p. 246), the possibility exists that non- 

 coagulable proteid substances ("seromucoid," etc.) may be 

 formed in the blood itself. And besides, autolytic ferments 

 exist throughout the body, and where small amounts of 

 albumose-like products are found in the blood they may as 

 well have come from autolysis of the hsemic proteins as from 

 the intestine as resorbed products of digestion. And finally 

 it may be very properly maintained that, even if small quan- 

 tities of digestion albumoses are positively detected, this 

 does not contradict the proposition that the bulk of the 

 products of digestion is resorbed only after complete 

 dissociation. 



23 G. Embden and F. Knopp, Hofmeister's Beitriige, 3, 120, 1903; L. Lang- 

 stein, ibid., 3, 373, 1903; G. v. Bergmann and L. Langstein, ibid., 6, 27, 1905; 

 F. Kraus (E. Freund's Labor.), Zeitschr. f. exper. Pathol., 3, 52, 1906; E. 

 Freund, ibid., 4, 3, 1907; O. Schumm, ibid., 4, 453, 1904; Erben, Zeitschr. 

 f. Heilk. (Inn. Med.), 24, 70, 1903. 



M R. Neumeister, Zeitschr. f. Biol., 24, 272, 1888; E. Abderhalden and 

 C. Oppenheimer, Zeitschr. f. physiol. Chem., 42, 155, 1904; E. Abderhalden, 

 Funk and London, ibid., 51, 269, 1907; O. Cohnheim, Nagel's Handb. d. Physiol., 

 2, 626, 1907; P. Morawitz and R. Ditschy, Arch. f. exper. Pathol., 54, 88, 1906; 

 S. B. Shryver (Univers. College, London), Biochem. Journ., 1, 123, 1906. 



25 E. Abderhalden, Biochem. Zeitschr., 8, 368, 1908; E. Freund, ibid., 7, 361, 

 1908; 9, 463, 1908; 11, 541, 1908. 



