MKMOllI.S OF TllK NATIO.NAI. .\( A I HvM V <>r sni;N( '|;.S. ;',;; 



Tlifsc p.t'panilioiis were next united suul Uis.solvod liy ImmIjii;,' in (iO \t,-v cciil aholnil; a var 

 iiisli like mass .Ifposifrd ..n (•o<.lill;,^ This process wa.s ropcatoil scvi-ial tiiin-s, ami the siihstaiici- 

 was tliiall.v tliifd wiih alisojui,. al.ohol. It ha<l tlit- rolhtwiiig compositiiin, as foinul in aualyscH 1 

 and 11 : 



The alcoholic solution after lono-ntratiiip: pave on cooliufj a preparation with 17.1' per rent 

 nitrogen. Kreusler rejocted the iii>;hcst earbon determination (..htained without the use of lead 

 dioxide) as probably erroneous, and wrote his analysis of oat glindin beside Hitthausen's of icheut- 

 (lliadin, as quoted above. Kreusler concludes that oatgliiwlin is e.s.sentially diHereut from wlieat- 

 gliadin, aud compares at length the behavior of tlie two towards reagents. The one i)oint of dif- 

 ference he mentions is that the oat-gliadiu dissolves in concentrated hydrochloric acid to a scarcely- 

 colored li(iuid, while wheat-gliadin gives a blue .sobition. ^ 



It is evident from Kieusler's i)aper that lie expected to tind the oat-protei<l sohible in alcohol 

 to have the same couipo.siti(m as wlieat-gliadin. lie finally accepted, as pure, a ])rcparation having 

 17.71 per cent of nitrogen, according ta a single determination. 



It is to be noticed on reviewing his analyses that the treatm»!nt to which Kreusler submitted 

 his preparations, while on tiie whole tending to raise the nitrogen content, sometimes ajjpears to 

 have had the opposite etl'ect, and the conclusion is not improbable that the lluctnations in the per- 

 centage of nitrogen found by him are partly attributable to the then unknown errors involved in 

 the soda lime method of analysis — errors which Ritthausen* and U. Kreuslcrf in later years fully 

 appreciated and mad(^ the subject of special investigation. 



111.— Oat Proteids Extracted by Weak Alcohol. 



(ft) TUK WIUTER's work. 



1. DIK'ECT EXTKACTION WITH ALCOHOL. 



As Ritthausen had .separated tln^ gliadin, mucedin and fibrin found by him in wheat gluten, 

 fi-om alcoholic .solution by fractional i)recipitation.s, the writer judged that if more than one pro- 

 teid were extracted from oats by alcohol, this fact would be shown by ditlcrences in behavior and 

 composition of various fra<;tions of the alcoholic extract. Accordinglyfour kilos of freshly ground 

 oats were heated on the water-bath with ten liters of alcohol of (*.!tl.'» sp. gr. After boiling for 

 half an hour the extract was strained through cloth, the residue pressed out and the extraction 

 repeated. The extracts were united, allowed to stand over night, decanted from sediment and 

 liltered clear. This solution was concentrated t<> one-third by distillation. After standing for 

 twenty hours at the temperature of the room, the residue deiwsited a bulky, yellowish precipi- 

 tate. .\bout four-lifths of the solution was carethlly decanted from this])recii>itate. The reuuiin- 

 ingone tifth could not be liltered until a large amount of strong alcohol had been added, which 

 caused the precipitate to separate. Alter liltering, the precipitate was treated with absolute 

 alcohol, next with ether, and after removing tlie ether with absolute alcohol again, and dried 

 over sulphuric acid. This preparation, ''1" then weighed 1.1..") grams and, dried at 110^ C, con- 

 tained i;5.!>L' ])er cent of nitrogen. The li(|uid decanted from 1 was still further concentrated t<) 

 about one-third of itx volume and cooled. The precipitate which formed "2" was treatt-d with ab- 



•Pfliiger-H Arcbiv 18. 23S (1878). 



tLuidv, Va-St. 24, 37 (1880): ibid. :i). -UH (18S&I. 



