VEGETABLE PROTEIDS. 



53 



yolks of fishes' eggs, and termed by them ichthin, ichthulin, and emydin, are 

 regarded by Hoppe-Seyler as doubtful chemical units, and are probably mixtures 

 of vitellin with nuclein and lecithin. Whether vitellin contains phosphorus in 

 its molecule or not is a moot point. Some regard it as a nucleo-proteid rather 

 than a globulin ; others look upon the phosphorus generally found in it as 

 belonging to either nuclein or lecithin, adherent to it as an impurity. The 

 same question arises in connection with phytovitellin (vegetable vitellin). 

 Kecent analyses by Osborne l show that it contains no phosphorus, though 

 Sachsse, one of the earlier workers, described the presence of this element. 



Proteids of flours. Sidney Martin 2 found the principal proteids in wheat 

 flour to be (1) a vegetable myosin, and (2) a soluble proteose, which he 

 called phytalbumose. 



Gluten is a mixture of two substances 



(a) Gluten fibrin, which is insoluble in alcohol, and formed from the 

 myosin ; and 



(b) A proteose insoluble in water, formed from the phytalbumose. This 



FIG. 11. Crystallised vitelliu of the oat kernel. After Osborne. 



insoluble proteose is, however, soluble in strong alcohol, and gives the sticky 

 consistency to gluten ; it corresponds to the two substances called gliadin and 

 mucediii by Ritthausen. 3 



The existence of proteids soluble in strong, though probably not in abso- 

 lute, alcohol, is a remarkable occurrence, and is not unique in vegetable 

 physiology. 



Martin considered that gluten does not pre-exist in wheat-flour, but is 

 formed on the addition of water by a ferment action. This is supported by 

 the fact that washing flour with water at a low temperature (2 C.) does not 

 lead to the formation of gluten. The ferment, however, has not been 

 separated, and Johannsen 4 has advanced certain facts that tell against the 

 ferment theory and in favour of the pre-existence of gluten in the flour. 



1 Am. Cliem. Journ., Baltimore, vol. xiv. No. 8. 



2 Brit. Med. Journ., London, 1886, vol. ii. p. 104. 



3 Journ. f.praU. Chcm., Leipzig, Bel. Ixxiv. S. 193, 384. For other observations on 

 gluten, see Bouehanlat, Compt. rend. Acad. d. sc., Paris, tome xiv. p. 962 ; Tarldei, Gior. 

 fisica di Hn/gnatdli, vol. xii. p. 860 ; Gunsberg, Journ. f. prakt. Chem., Leipzig, Bd. 

 Ixxxv. S. 213. 



4 Ann. agronomiqucs, Paris, tome xiv. p. 420. 



