54 CHEMICAL CONSTITUENTS OF BODY AND FOOD. 



Osborne l investigated the proteids of the oat and analysed three primary 

 oat proteids, one soluble in alcohol, the second a globulin, and the third a 

 proteid soluble in alkali only. From these, secondary proteids are obtained 

 by mixing the ground oats with water ; he regards the change as one pro- 

 duced by ferment activity. 



In conjunction with Chittenden, 2 he worked out in a similar way the 

 proteids of maize, and found there two globulins, one or more albumins, and a 

 proteid soluble in alcohol. These differ in solubilities, coagulating points, and 

 elementary composition ; one of the globulins is a vitellin, the other a myosin. 

 A small amount of proteose also present was regarded as artificially produced 

 in the processes of analysis. The proteid soluble in alcohol is called zein ; 

 and it, like the globulins, is converted into an insoluble modification on ad- 

 mixture of the flour with water. 



The proteids of flax seed 3 he foiled to be chiefly globulin, with smaller 

 quantities of albumin, proteose, and peptone. 



In wheat Osborne and Voorhees 4 describe five proteids : 



1. Gliadin; a proteid soluble in alcohol, and like gelatin in some of its 

 other properties. 



2. Glutenin ; a proteid soluble only in alkalis. 



3. Edestin ; a globulin of the vitellin class. 



4. Leucosin ; an albumin, which Martin described as a myosin. 



5. Proteoses. 



They do not agree with Martin's ferment theory of gluten formation. 

 O'Brien 5 has arrived at a similar conclusion ; he regards gluten formation as 

 due to hydra tion, though not produced by a ferment. The proteids in the 

 flour he describes as globulins of the myosin and vitellin type, and a 

 proteose which he regards as the mother substance of gluten. 



Other vegetable proteids investigated by Osborne are those of the kidney 

 bean 6 (two globulins called phaseolin and phaselin, and proteose) ; of the 

 cotton seed (almost altogether proteose, with small amounts of edestin and 

 insoluble proteid) ; of rye (gliadin, leucosin, edestin, and proteose) ; and of 

 barley 7 (leucosin, proteose, edestin, and hordein, an insoluble protoid, 

 corresponding to Kitthausen's mucedin). He also investigated the chemical 

 nature of diastase, and considers it is closely related to the albumin he has 

 named leucosin. 



Researches on proteolytic ferments in plants. Those in the papaw plant 

 and in pine-apple juice are the best known, or most fully worked out. 



Papain was the name given by Wurtz to the proteolytic ferment in the 

 juice of the papaw plant. 8 The close similarity of its action to that of 

 trypsin was shown by S. Martin. 9 The proteids in the juice are a globulin 

 very like serum globulin, small quantities of an albumin, and proteoses of 

 two kinds, with one of which the ferment appears to be closely associated 

 (Martin). 10 



Bromelin. This is the proteolytic ferment in pine-apple juice. Its 

 existence was first noted by Marcano of Venezuela. It is made use of 

 extensively in South America for the preparation of artificially digested 



1 Am. Chem. Journ., Baltimore, vol. xiv. No. 3. 



2 Ibid., vol. xiii. Nos. 7, 8, and 9 ; vol. xiv. No. 1. 3 Ibid., vol. xiv. No. 8. 



4 Ibid., vol. xv. No. 6; "Seventeenth Ann. Rep. Connecticut Agric. Expt. Station," 

 Newhaven, 1893. 



5 Ann. Botany, Oxford, 1895, vol. ix. pp. 171, 503. 



6 Journ. Am. Chem. Soc., N. Y., 1894, vol. xvi. p. 633. 



7 Ibid., 1895, vol. xvii. p. 539. See also Osborne and Campbell on proteids of potato 

 on conglutin and vitellin, on legnmin and other proteids of the pea and vetch, ibid., 1896 

 vol. xviii. No. 7. 



8 Compt. rend. Acad. d. sc., Paris, 1879, p. 425 ; 1880, p. 1379. 



9 Journ. Physiol., Cambridge and London, vol. v. p. 213. 

 10 Ibid., vol. vi. p. 336. 



