219 



carried 'tut by placing a small quantity of flour in a beaker, covering the top with the 

 bolting doth held in place by means nt' a rubber band, inverting and shaking. <>p.-i 

 aliiii; "ii tin- .-in f.l mati-cial. as little as > per cent of wheat Hour in buckwheat flour 

 may be detected . In pure buckwheat flour 1 have n-\ er obtained a visible amount 

 of gluten. 



Figure <;, reproduced from photograph-; male by Mr. 15. .) . Howard, Thief of the 

 Microchemical Laboratory, IJurcau of < hemistry, shows the gluten obtained by this 

 te-t in pure rye Hour, a mixture of >() |>er cent rye flour and 40 per cent wheat flour, 

 and pure wheat Hour, iiiairniu'ed 1 diameters. As has been stated, in practical work 

 no nuiLMiilication whatever is necessary to bring >"t the gluten strings or masses. 



MOISTURE DETERMINATIONS WITHOUT THE AID OF HEAT. 



p.y r. i' TI:I>\VIII{II><;K. 



For more than a year at the Missouri experiment station the moisture determina- 

 tions on meats have been made without the aid of heat, by drying in vacuum OV6T 

 sulphuric acid. At tit>t the ordinary brass filter pump wa< u-ed for obtaining a 

 vacuum, aided by the u-e of about 10 cc of ether i Benedict method). A vacuum of 

 I or _' mm is ea.-ily obtained \\ith 'jood water pre.-sure. but in warm weather many of 

 the samples would show some putrefaction I n was complete enough 



to cheek decomposition. It was n..ted that the water formed with the acid an upper 

 Mntod < ,,11-iderable heat when mixed by rotation. This suggi-ted 

 the frequent agitation of the sulphuric arid in the bottom of the desiccator-, with 

 the result that twel\e hour- \\as sullicient to dry fresh meat samples so that they 

 would not putrefy. Ha\ . : -rabh- difficulty with the water pressure, a (Jer\ k 



duplex vacuum pump was procured, and without tl iier a vacuum of less than 



1 mm was secured in two ., r three minutes. 



SubstanceseU' in and II\T gavt much trouble by frothing out. of the mois- 



ture i i usted, but the difficulty was ob\ iated by freezing 



lhe.-e -ample- al'lel" |h--> U-!,- 'A . IJ 1 1 . I ^l!llllall\ . .M -\\.iter e\!ra,t- o| i.rel U elV 



i and e\a|orate<! to dry ness in the vacuum without e\er thawing, lea\ in-j tin- 

 dry substance as a web-like mass the full .-i/.e of the original : Tact. 



The inoi-niM- ir.-e samples are UBt'd for d- terminal ion of the ether-.-oluhle material. 



:d, horn-like mass, BO that it is necessary to^rind 



them and make a sen >i id extraction in onler to obtain all of the ether-soluble mat. rial. 

 In order to avoid this difficulty, the meat samples are mixed with ignited .-and. and 

 such good results are obtained that a desc -riptioii of the method may be of interest. 



l-'..r the ni"i-Mire and fat tubes use either the S. & S n -hell- ,,r the glass 



tubes w ith filter-paper bottom-. Fill the tube about one-third full of ignited 

 and then stuff in a liberal amount of fat free cotton. l>rv the tube- thus prepared i they 



should be numbered) for several hours intheovenat L03C., and place in a vacuum 



ie\v hour- i'_'hiii_- U'l-i'/h ill a glass-stoppered \\ej./hin^ bottle and 



.'lit of the tube and bottle o .n.-erut i \ el\ . This Uei-hilP_' is done in 



advance of a ?-lau.i;hterin'.r experiment, and several hun<lred tubes are prepared. 



IMace the finely Around and thon.u^hlv mixed samples of meats in wei'/hiii^ bottles 



Erovidetl with ihorl aluminum scoops (a heavy piece of stirring rol will do , and weigh 

 y difference, usin-r fn-m ."> to 10 Drains for a sample. K-ino\e the cotton from one of 

 the lan-d tabes, placing it mi the side of a flat inaUow p<n-elain dish, and carefully 

 pour out the -and into the dish. Place the sample of the meat upon thesandand mix, 

 u-ini: a -patula and a stirring nl. When the sand and sample are thoroughly mixed, 

 tran.-fef the ma.-s to the tube, u-iiii: the <-otti>u to wipe all trace- from the dish, the 

 spatula, and the stirring rid. Loss of any particles ..f sand is prevented by working 

 over black glazed paper. The last of the unused cotton is placed in the top Of the tube 

 as a plu'j. 



Make the determinations in triplicate and place them in separate desiccators. (We 

 use a good U-inch vacuum desiccator. Larger desiccators were tried, but several of 

 them broke, owinir to the hiu'h pres.-ure. i Wire-gauze baskets are used, which set on 

 the porcelain desiccator plate. In this basket from eight to twelve tubes can be 

 placed. The desiccator coven and stopcocks must be well ground and a lubricant 



