CHEMISTRY. 371 



The proteids of the potato, T. J>. Osborne and G. F. Campjjell 



[Connecticut iStatc iSta. l\pt. 1805, pp. 255-:2(il). — Brief ref'ereuce i.s made 

 to previous work on this subject by other investigators. The details of 

 the niaiiipulation of the pulp and isolation of the proteids are described. 

 In general, these methods were similar to those followed by the authors 

 in previous investigations. The proteids were found to consist of a 

 globulin, for which the name tuberin is proposed, and a i)roteose, occur- 

 ring only in very small amount. The properties of the tuberin are 

 described as follows: 



" [Tuberin] is precipitated l>y s.aturatiug its solutions with sodium clilorid, sodium 

 sulphate, magnesium sulphate, or ammonium sulphate. By acetic acid or nitric acid 

 a precipitate is given readily solu)>le in an excess of acid even in the piesence of 

 salts. I'otassium fcrrocyanid gives no precipitate until acetic acid is added. Mer- 

 curic chlorid gives no precipitate, but picric acid or tannic acid throws down the 

 globulin. With the biuret, Millon's, and the xanthoproteic tests the usual reactions 

 are giveu. 



"Tuberin is soluble in very dilute saline solutions, and therefore the juice of the 

 potato contains the greater part of this proteitl. By dialysis it is precipitated 

 slowlj' and incompletely because of the difficulty of removing all soluble salts by 

 this process. Like other easily soluble globulins, it readily changes to the insoluble 

 modification, so that preparation's made by dialysis are to a great extent insoluble 

 in saline solutions. In contact with alcohol it very quickly loses its solubility. 



"\\'heu <lissolved iu 10 jx'r cent sodium chlorid solution, tul)eriu shows a somewhat 

 variable heat-coagulaticm point, depending on the conditions under which it is tested. 

 In general, a flocculent coagulnm is formed on heating to 60 to 65° ('. Coagulation is, 

 however, not complete until the solutions ha\e been heated for some time at 80 C. 

 The composition of this glol)uliu was found from an average of several accordant 

 analyses to be : 



Tiibcrin from potato. 



Per cent. 



Carbon ,53. 61 



Hydrogen 6.85 



Nitrogen KJ. 24 



Sulphur 1.25 



Oxygen 22. 05 



100. 00 



Legumin and other proteids of the pea and the vetch, T. B. 



OsBOKNE and G. F. Campbell {Connectievt State iSta. Rpt. 180'), pi>. 

 2(J2-:3S7). — "In recent literature legumin is most commonly referred to 

 as a substance extracted from seeds by caustic alkalies, and more or 

 less altered by the action of the solvent; but nothing has been done, to 

 our knowledge, to show the nature of the original proteid. 



"The object of our investigation has been to examine the seeds in 

 which legumin is said to exist, and to determine as delinitely as possi- 

 ble the composition and character of this substance." 



The literature of legumin is reviewed, and the details are given of 

 the authors' investigations on the legumin and other jjroteids of the 

 common garden pea and the common vetch. The results of these in- 

 vestigations are concisely summarized l)y the authors as follows: 



"(1) So far as we have investigated, peas and vetches contain the same proteids, 

 which are nearly if not entirely soluble iu 10 jier cent sodium chlorid solution. 



