664 EXPERIMENT STATION EECORD, 



}j;luten feed. The relative prices may vary soinewliat in ilitTereut localities, but 

 lu general it is probably safe to say that these will be the cheapest feeds this 

 season. The most expensive feed . . . [included in the comparison] is alfalfa 

 meal, the next most expensive linseed meal." 



The chemical and physiolog'ical properties of cell walls, A. Fukstenberg. 

 R. MuRDFiELD, and J. Koxio (Laiidir. ] cr.s. Htat.. (!■') {lHOiJ), Xo. 1-2, pp. 55- 

 110). — The chemical and physiological experiments reported led to a number of 

 conclusions, among which are the following : 



The glycerin-sulphuric acid method was found to be satisfactory even for 

 cellular tissue rich in pentosans. When the crude fiber of feces was treated 

 with glycerin-sulphuric acid, the hemicelluloses and the pentosans were very 

 thoroughly dissolved, so that this method seems the preferable one even for 

 materials rich in lignin. The difficultly soluble portion of cell membrane desig- 

 nated crude fiber in food and feeding stuff analyses consists of 3 groups of dif- 

 ferent properties and with different carbon content, namely, (1) a cellulose group 

 with 44.44 to 40 per cent carbon, which is soluble in copper oxid and ammonia ; 

 (2) the portion of the lignin group which can be oxidized with hydrogen per- 

 oxid and ammonia and has a carbon content of 55 to 60 per cent; and (3) 

 " kutin," which has even a higher carbon content and is not oxidized by either 

 of the reagents mentioned. The cellulose group is quantitatively soluble in 

 copper oxid and ammonia only after the removal of the portion which can be 

 oxidized. The crude fiber which remains after the i-emoval of lignin and kutin 

 and which is soluble in copper-oxid ammonia and gives a violet color with 

 chlorid of zinc and iodin and a blue color with suli)huric acid and iodin, does 

 not always possess the composition of true cellulose, but sometimes shows a 

 higher carbon content owing to the addition of methyl or methoxyl groups. 

 Such cellulose has been identified in rye and wheat bran and in very small 

 quantity in barley bran. 



Methoxyl, ethoxyl, or acetyl groups are present in larger proportion in lignin, 

 but are entirely absent in kutin. Lignin is evidently not a simple body, but con- 

 sists of a number of carbon radicals united to cellulose. 



The proportion of kutin in crude fiber is by no means small. According to 

 the analyses which have been made it ranges from 0.64 per cent in pea bran to 

 13.67 per cent in wheat bran, and from 0.70 per cent in pea bran feces to 19.05 

 per cent in wheat bran feces. 



As is well known, the percentage content of crude fiber in plants increases 

 with age. On the other hand, the lignin content increases more rapidly than 

 the cellulose. No fixed relation is ai)parent between kutin content and jilant 

 growth. 



The digestibility of the cell membrane of coarse fodders by sheep is inversely 

 proportional to the lignin and kutin content. Cellulose is the most thoroughly 

 digested of the crude fiber constituents. Lignin is very resistant to the diges- 

 tive juices of herbivora and is only utilized to a very small extent. If kutin 

 is utilized at all it is only in very small quantity and when it occurs in very 

 young plants. With pigs the digestibility of the crude fiber of bran, with the 

 exception of pea bran, is very slight, as is also the case with rabbits. That 

 portion of the crude fiber which contains the lower percentage of carbon has 

 a higher digestibility than the portion with the high car.(on content. These 

 animals also digest kutin very little if at all. 



Since the digestibility of crude fiber in general is inversely proportional to 

 the lignin and kutin content, it seems probable that the lignin and kutin, or 

 the latter alone, surrounds the cellulose or is deposited in it in such a way 

 that the action of the digestive juices is hindered. These things being so, it is 



