236 ALBUMINOIDS. 



rapidly filtered off with the help of a filter-pump, washed with 40 

 to 60 per cent, spirit, finally with absolute alcohol and. with ether, 

 dried and weighed. 



§ 227. Isolation of Fitellin,etc. — Grains of vitelline (aleurone, etc.) 

 may be frequently isolated from substances containing them in 

 large quantities, by a process of elutriation with olivjB oil,^ or a 

 mixture of oil and petroleum spirit.* Freed from oil with 

 petroleum spirit, vitellin dissolves in water at 30° to 40°, and can 

 be precipitated from such a solution by a current of carbonic acid. 

 To obtain it in crystals the precipitate is digested with calcined 

 magnesia at 35°, filtered whilst warm and cooled. Schmiedeberg 

 considers these crystalloids, as well as aleurone itself, to be 

 compounds of viteUin with alkalies or alkaline earths. The 

 crystals are doubly refracting. 



§ 228., Separation of VUellinfrom Myosin. — According to Weyl,* 

 vegetable vitellin may be distinguished from vegetable niyosin by 

 requiring, in a solution containing 10 per cent, of common salt, a 

 temperature of 75° for coagulation, whilst myosin coagulates at 

 55° to 60 . The latter, which has also been found in potatoes, 

 passes into solution ^hen the residue, after treatment with water, 

 is macerated with 10 per cent, solution of salt. Small pieces of 

 rock-salt suspended in such a solution (previously neutralized with 

 carbonate of soda) cause the gr'adual precipitation of the myosin, 

 which, however, can be redissolved by the addition of a little 

 water. Myosin may be separated from vitellin by diluting the 

 solution largely with water, precipitating both with carbonic acid, 

 dissolving in dilute salt-solution and coagulating at the tempera- 

 ture stated. 



§ 229. ^simaiion. -^Experiments made by Liborius,^ Girgen- 

 sohn,^ and Taraskewicz,^ have shown that the albumen of blood 

 serum, eggs, etc., can be estimated with tolerable accuracy by 



^ A similar substance occurs in the seeds of Pinus cembra. See Schuppe, 

 Pharm. Zeitschr. f. Eussland, 520, 1880. 



" Compare Maschke, Ohem. Centralblatt, 864, 1858, and Saohsse, ibid. 583, 

 1876 (Joum. Ohem. Soc. xxxii. 200). 



'Compare Schmiedeberg, Zeitschr. i. phys. Chem. i. 206; Ritthausen, 

 A.rohiv f. die ges. Phys. xvi. 301 (Journ. Chem. Soo. xxxiv. 518). 



* Loc. cit. ■ 



'^ 'Beitr. ». quant. Eiweissbest. Diss. Dorpat, 1870. 



' ' Beitr. z. Albuminometrie und z. Kenntniss d. Tanninverb. d. Albuminate. 

 Diss. Dorpat, 1872. 



' Einige Methoden z. Werthbest d. Milch. Diss. Dorpat, 1873. 



