ix THE VEGETABLE ALBUMINS 371 



have been investigated very thoroughly. Starting with Liebig, a large 

 number of papers have been published dealing with these readily 

 accessible and economically very important bodies. We owe to Ritt- 

 hausen l a special debt of gratitude for the careful way in which he 

 analysed, and also determined the solubilities of, a large number of 

 different albuminous substances belonging to the cereals and to pulse 

 (beans, peas, lupines, etc.). As the methods employed by Ritthausen did 

 not guarantee that he had isolated chemical individuals, his observations 

 received for a long time little attention ; but through the work of 

 E. Schulze and Kossel, who analysed Ritthaussen's substances, the im- 

 portance of the latter's investigations was proved. The dissociation 

 products are given in the Tables, pp. 71-72, Nos. 13 to 24. 



Better denned from a chemical point of view are a series of albu- 

 mins which occur in a crystalline form 2 in hemp, the Para-nut, in the 

 seeds of the cucumber, and in the castor-oil plant. These albumins 

 have also been prepared in a crystalline form from their solutions, 3 

 and they were the only crystalline albumins known till egg- and serum- 

 albumin were crystallised. At present edestin and oxyha3moglobin are 

 probably the two purest albuminous substances we possess. More 

 recently this group of substances has been investigated especially by 

 Osborne (see later). 



Most of the vegetable albumins are globulins, i.e. acid -albumins 

 which are insoluble in pure water, but soluble in salt-solutions, and 

 precipitable by dilution and acidification ; they are known collectively 

 as phyto-globulins. Some of the vegetable albumins contain phos- 

 phorus, and not merely as an admixture, in their molecule, according 

 to Liebig, 4 Ritthausen, Palladin, 5 and Wiman. 6 They resemble the 

 true nucleo-albumins in being insoluble in neutral salt-solutions, but 

 they are soluble in alkalies. Liebig gave to these substances the name 

 of vegetable casein, but they are now, following Weyl, 7 usually called 



1 H. Ritthausen, Die Eiweisskorper der Getreidearten, Hillsenfruchte und Olsamen, 

 Bonn, 1872 (abstract of his own work and that of his pupils, published mostly in the 

 Journ. f. prakt. Chem. ; here also the older literature). See also Pfluger's Arch.f. d. ges, 

 Physiol. 15. 269 (1877) ;. 16. 293 and 301 (1878) ; 18. 236 (1878) ; Journ. f. prakt. 

 Chem. (2) 23. 412 (1881)'; 24. 221 and 257 (1881) ; 25. 130 (1882). 



2 Hartig, Botanikerztg. 13. 881 (1855) ; 14. 257, 297, and 313 (1856) ; Maschke, 

 ibid. 17. 409 and 417 (1859). 



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

 physiol. Chem. 1. 205 (1877). 



4 J. v. Liebig, Liebig s Annalen, 39. 128 (1841). 



5 W. Palladin, Zeitschr.f. Biol. 31. 191 (1895). 



6 A. Wiman, Malys Jahresber. 27. 21 (1897). 



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

 Chem. 1. 72 (1877). 



