ABSTRACTS OF REPORTS OF FOREIGN INVESTIGATIONS. 



On the determination of crude fiber, S. Gabriel iZrilxdi. f. phi/s- 

 iol. C'ltrin., Jii,j)i).-j:U-j"-t>). — The author iiiatic a ciitical study <»f lliiuig's 

 method for cellulose detenninatioii, wiiidi depends on eoiiveiting 

 tlie albuminoids and starcli into soluble coniiMtunds by lu-atiii.c with 

 glycerin at L'KTC. This method in its ori^iinal loini was found to be 

 unreliable for the analysis ol vegetable i)rodncts. Neither all of the 

 l»rot<'in nor of the nitrogen- tree substances were converted into soluble 

 coini>ounds, over l.r> jter cent of nitrogen remaining in the cnnle celbi 

 lose. He then set about eliminating the errors of the method by modi- 

 lications. It was foun«l that when L* grams of potassium hydrate was 

 dissolved in <iO c. c. of glycerin and this mixture was heated with L' 

 grams of yellow lupine seed at ISO' (', tlie results very nearly 

 approached those by the AVeende method, and the nitrogen remaining in 

 the enule cellulose was reduce<l to a minimum (O.OS to 0.1 jter cent). 

 But when this method was a]»])lied to hay, sheep dung, barley straw, 

 oats, beets, potatoes, and beech wootl the results agn'e<l with those of 

 the Weende method in some cases, and in others were as much as \ 

 per cent higher. In the case of every sul»stanc»', however, the nitrogen 

 in the c«'lbilose was very low — lower than with the Weench' method. 



Crude cellulose lueparcil by the two methods was tested for non- 

 cellulose, nitrogen free substances, by means of hydrolysis and Fehling's 

 solution. Tliat ])rei>aied by both methods was found to contain these 

 substances, often in considerable quantities; and si)ecial tests indi 

 cated that the reduction of copi)er was not due to hydrolysis of the 

 cellulose, as the acid used was without eftert njion it. But as these 

 nitrogen-free sulistances were so easily inv«'ited and ren<len'd soluble, 

 by acid which had no efl'ect u]>on the cellulose itself, the method was 

 moditied to inclmb' this digestion with acid. Triplicate determinations 

 were then made of the cellulose in yellow lu]»ineseed. hay, shee|>dung, 

 barley straw. (r,\\s. beets, and beech wood, digesting with glyt-erin- 

 alkali solution lirsf. and alterwards with (•.«> ])er cent hydrochloric 

 acid to n-move any nitrogen free substances t»tln'r than cellulose 

 remaining, 'i'he averages of these deteiniinations as compared with 

 those by tlie Weende method were, in terms of nitrogen-free and ash- 

 free cellulose, as follows: 

 910 



