198 CHEMISTRY OF THE PROTEIDS CHAP. 



Jacoby, 1 Kutscher and Lohmann 2 (pancreas), Levene 3 (testis, spleen), 

 Hildebrandt 4 (mammary gland), Lane, Claypon, and Schry ver 5 (gastric 

 and intestinal mucous membrane), Waldvogel 6 (autolysis in relation 

 to fatty degeneration), Schulze and Castoro 7 (germinating plants), 

 and many others in all the organs of the body. They dissociate the 

 tissue -albumins into albumoses and amino- acids. It has not yet 

 been settled whether the autolysis is induced by special ferments 

 or only by traces of pepsin, trypsin, and erepsin. According to Hedin 

 and Rowland 8 these autolytic ferments act best in acid media. 



Ferments which dissociate albumins into amino -acids are very 

 widely distributed in nature, and occur probably in all animals ; as 

 intermediate products peptones are usually formed. Mack 9 has pre- 

 pared such peptones, under the direction of Siegfried, from the seeds 

 of Lupinus luteus. These peptones resemble in their properties and 

 dissociation -products the trypsin-peptones. The ferments under 

 discussion must not be identified, without proper reasons, with trypsin, 

 as many of them act only in acid or in acid and alkaline solutions. 10 

 Many bacteria contain these ferments, 11 as does also yeast. 



The ferments in germinating plants have already been mentioned. 

 In some portions of plants, Vines 12 and Czapek 13 have found erepsin- 

 like ferments. A ferment which in acid media dissociates albumins 

 up to the stage of amino-acids is the ' bromelin ' 14 of pine-apples. The 

 ferment 'papaj^otin' found in the juice of Carica papaya has been 

 carefully examined by Neumeister, 15 Mendel, 16 Ingraham, 17 Kurajeff, 18 



1 M. Jacoby, Zeitschr. f. physioL Chem. 30. 149 (1900) ; 33. 126 (1901) ; Hof- 

 meisters Beitrdge, 3. 446 (1903). 



2 Kutscher and Lohmann, Zeitschr. f. physiol. Chem. 41. 332 (1904). 



3 P. A. Levene, Amer. Journ. of PhysioL 11. 437 (1904). 



4 P. Hildebrandt, ffofmeister' s Breitrage, 5. 463 (1904). 



5 J. E. Lane, Claypon, and S. B. Schryver, Journ. of Physiol. 31. 169 (1904). 



6 Waldvogel, Virchow's Arch. 177. 1 (1904). 



7 E. Schulze and N. Castoro, Zeitschr. f. physiol. Chem. 43. 170 (1904). 



8 S. G. Hedin and S. Rowland, ibid. 32. 341 (1901), 32. 531 (1901). 



9 W. R. Mack, Dissertation, Leipzig, 1903. 



10 W. Biedermann, ' Tenebrio molitor,' PflilgersArch.f.d.ges. Physiol. 72. 105 (1898). 



11 M. Hahn and S. Geret, Zeitschr. f. Biol. 40. 117 (1900) ; Zeitschr. f. physiol. 

 Chem. 33. 385 (1901) ; F. Kutscher, ibid. 32. 59 (1900), 32. 419 (1901), 34. 517, 

 520 (1902) ; E. Salkowski, ibid. 13. 506 (1889). 



12 S. H. Vines, Annals of Botany, 17. 237 (1903), 17. 597 (1903), 18. 289 (1904). 



13 F. Czapek, Chem. Zentralbl. 1903, p. 178. 



14 R. H. Chittenden, Journ. of Physiol. 15. 249 (1883). 



15 R. Neumeister, Zeitschr. f. Biol. 26. 57 (1890). 



16 L. B. Mendel and F. P. Underhill, Trans, of the Connecticut Academy of Arts and 

 Sciences, XI. October 1901 ; L.B. Mendel, Amer. Journ. ofMed. Sc. 124. 310(1902). 



. 17 L. B. Mendel. See footnote, ibid. p. 318. 



18 D. Kurajeff, Hofmeister's Beitrdge, 1. 121 (1901). 



