Experimental and Applied 271 



(i p.ct. HC1), and again washed off cold and hot. The residue 

 from this treatment is defined as ' permanent tissue.' 



If, now, a plant or plant-substance were to be investigated con- 

 taining a large portion of starch, it would be necessary to precede 

 these hydrolytic treatments by a process acting selectively on the 

 starch, viz. the substances reduced to a fine state of division, boiled 

 for a short time with water, left to cool, and treated with malt ex- 

 tract, being digested for some hours at the most favourable tem- 

 perature for conversion. After this, which should follow the alcoholic 

 exhaustion, the remainder of the processes may be proceeded with 

 in order. (Compare V. Stein, Exper. Stat. Record, 5, 613, from 

 Ugeskr. f. Landmand, 39, 706.) Such a residue will contain a cer- 

 tain proportion of ash constituents and nitrogen, for which, in certain 

 cases, allowance must be made, by the usual methods of determining 

 and calculating. The difference between this product and that 

 known as * crude fibre ' (Weende method) will be noted. The im- 

 portant aspect of these methods and their differences is appreciated 

 in dealing with a complex such as the constituents which yield 

 furfural. Of these, the product known as wood gum (pentosan) is 

 soluble in dilute alkaline solutions in the cold, and would be elimi- 

 nated under these treatments ; but the furfural-yielding constants 

 are only partially eliminated by the treatment, even from non-ligni- 

 fied tissues. But, in the mean time, it is not safe to follow on the 

 older lines, which usually were held to sharply divide group from 

 group. We may affirm generally that no hydrolytic process can 

 effect any such separation, and this is particularly to be noted in re- 

 gard to the furfural-yielding constituents. It is advisable, therefore, 

 to bear in mind that any process selected is more or less arbitrary, 

 and gives results which, while they may be perfectly valid under 

 conditions of strict comparison, are not to be interpreted outside 

 these comparisons except with reservation. This will be specially 

 appreciated when the results of the proximate analyses are taken 

 as evidence of feeding value. This entire subject is very much in 

 need of revision, and we hope that both the theoretical matter and 

 the experimental methods described in this treatise will contain 

 suggestions of methods by which these problems can be more 

 effectively solved. 



The Analysis of Textiles and Paper. The various processes of 

 quantitative determination that have been described are available 



