BULLETIN OF THE BUSSEY INSTITUTION. 397 
As I have set forth in a previous paper,* date stones are an ap- 
proved food for camels, and the coarse powder of the ivory nut 
has been used, even in this country, for feeding horned cattle. 
Both cattle and sheep eat the meal with great relish and fatten 
upon it.f In respect to their chemical composition, both these 
substances are akin to palm nut cake,{ which has been used exten- 
sively in Europe for feeding cows and which is held to be a 
peculiarly excellent fodder. ‘The point of interest is that the hard 
date stones and ivory nut (and the palm nut cake) contain a great 
store of  hexosans while sawdust consists largely of the pentosan 
xylan. 
The question whether the actual sugars (pentoses) derived from 
pentosans are assimilable by animals has been discussed by several 
chemists,§ but in the light of the evidence thus far accumulated it 
would seem that at the best the pentose sugars must be regarded 
as very much less valuable foods than the hexose sugars. 
As for the pentosans themselves, in the condition in which they 
occur in vegetable matters, Stone || has expressed the convietion— 
based on the results of many experiments made by him — that the 
pentosans are to a marked degree less digestible than the better 
known hexosans and that they are of less value than the latter as 
eattle food. This conclusion was foreshadowed by a notable 
experiment made — at the suggestion of Professor Engelhardt of 
St. Petersburg— by a student named Gudkow ** who fed a pig for 
a month with nothing but wheat-bran and observed that the excre- 
ments of the animal contained a much higher percentage of xylan 
than was contained in the original bran. TT 
* See Bulletin of the Bussey Institution. 1876, 1. 373. 
+ Report of the Connecticut Agricultural Experiment Station. 1880, p. 86. 
Liebscher and Schuster, Landwirthschaftliche Jahrbiicher. 1890, 19. 143, 155. 
t Press cake from the seeds of the oil palm, Llaeis Guineensis. 
§ Notably by Goetze and Pfeiffer, Versuchs-Stationen. 47, 80, 93; Cf. 
Ibid. 49. 108, and Weiske, Zeitschrift fiir physiologische Chemie. 20. 488. 
|| American Chemical Journal. 14. 13; further, Agricultural Science. 
7.19. See also, Weiske, Zeitschrift fiir physiologische Chemie. 20. 488, 
and F. Lehmann, as cited in Landwirthschaftliche Jahrbiicher. 21. 98. 
** Zeitschrift fiir Chemie. 1870 [N. F.], 6. 360, 363, 365. 
++ It is worthy of remark that the work of Gudkow (and Engelhardt) did 
much more than exhibit the ditlicult digestibility of the pentosans in bran. 
Pains were taken to prove that bran contains a peculiar substance from which 
furfurol is obtained on distilling it with acids, and a new kind of sugar (now 
known to be a pentose) was prepared from the substance which yields fur- 
