372 CHEMISTRY OF THE PROTEIDS CHAP. 



phyto-vitellins. What makes the investigation of these compounds 

 especially difficult is the presence of considerable amounts of salts such 

 as potassium-, calcium-, or magnesium-phosphates, or of alkalies in com- 

 bination with organic acids. These salts are frequently the real cause 

 of the acid or alkaline reactions given by phyto-vitellines. Tannin is 

 frequently also present, and will precipitate albumins whenever the 

 reaction becomes acid. 1 In many instances the salts of the albumins 

 have been studied instead of the free albumins, 2 and in other cases 

 special deductions had to be made, to allow for the ash constituents 

 which have been carried down mechanically during coagulation. For 

 all these reasons it is, in many cases, impossible to tell whether we 

 are dealing with globulins or with vitellines, and for this reason all 

 these albuminous substances, being biologically allied, have been classed 

 together. Palladin 2 has shown that the so-called plant-myosin is 

 merely the calcium salt of vitelline (Cohnheim). 



1. Edestin 



Weyl, 3 Schmiedeberg, 4 Drechsel, 5 Chittenden and Hartwell, 6 and 

 Osborne r have found in the Para-nut (Bertholletia) an albumin, the 

 lime or magnesium salts of which crystallise out in well-formed octo- 

 hedra. Griibler 8 and Ritthausen 9 found a similar albumin in cucumber 

 seeds. Subsequently Ritthausen, 9 Osborne, 10 Chittenden arid Mendel, 11 

 Leipziger, 12 and others prepared from hemp-seed a substance which, in 

 its composition and all its properties, fully agrees with the globulin 

 prepared from the Para-nut, and which has been called ' edestin ' by 

 Osborne. Later on Osborne obtained edestin also from the seeds of 

 the castor-oil plant, 10 the flax, 10 the oat, 13 cucumber, 10 maize, 14 different 



1 H. Ritthausen, Journ.f. pmkt. Chem. (2) 24. 257 (1881). 



2 W. Palladin, Zeitschr.f. Biol. 31. 191 (1897) ; T. B. Osborne, Journ. of the Amer. 

 Chem. Soc. 21. 486 (1899). 



3 Th. Weyl, Pluger's Arch. f. d. ges. Physiol. 12. 635 (1876) ; Zeitschr. f. physiol. 

 Chem. 1. 72 (1877). 



4 G. Griibler, Journ.f. prakt. Chem. 131. 97 (1881) ; 0. Schmiedeberg, Zeitschr. f. 

 physiol. Chem. 1. 205 (1877). 



5 E. Drechsel, Journ. f. prakt. Chem. (2) 19. 331 (1879). 



6 R. H. Chittenden and J. A. Hartwell, Journ. of Physiol. 11. 434 (1890). 



7 T. B. Osborne, Amer. Chem. Journ. 14. No. 8 (1893). 



8 G. Griibler, Journ. f. prakt. Chem. 131. 97 (1881). 



!t H. Ritthausen, ibid. (2) 23. 412 (1881) ; (2) 25. 130 (1882). 



10 T. B. Osborne, Amer. Chem. Journ. 14. No. 8 (1893). f^r 



11 R. H. Chittenden and L. B. Mendel, Journ. of Physiol. 17. 48 (1894). 



12 R. Leipziger, PJl'dger's Arch. f. d. ges. Physiol. 78. 402 (1899). 



13 T. B. Osborne, Amer. Chem. Journ. 14. 212 (1893). 



14 T. B. Osborne, Journ. of the Americ. Chem. Soc. 19. 525 (1897). 



