8!)H 



PRACTICE OF AGRICULTURE. Part III. 



5722. On the nutritive products, Sir II. Davy has the following valuable remarks, some 

 of which, concerning the mode in which the animal economy is operated on by the 

 different substances composing the nutritive .natter, the agriculturist will find useful, as 

 applied to the tables before given (.5000. 5190. &c.) of the nutritive products of the 

 corns, legumes, and roots. The only sub-.tances which Sir II. Davy detected in the 

 soluble matters procured from the grasses, are mucilage, sugar, bitter extract, a substance 

 analogous to albumen, and different saline matters. Some of the products from the 

 aftermath crops gave feeble indications of the tanning principle. In the experiments 

 made on the quantity of nutritive matter in the grasses, cut at the time the seed %vas ripe, 

 the seeds were always separated; and the calculations of nutritive matter made from 

 grass and not hay. 



5723 The order in which these tubstaneet are nutritive is thus given : — " The albumen, sugar, and mu. 

 cilageTprobably when cattle tee,! on grass or hay, arc for the most part retained in thebodyo theannnal; 

 andlne bitter principle, extract, saline matter, and tanmn, when any exist, probably for the «<**£«* 

 are voided in the excrement, with the woodv fibre. The extractive matter obtained by boiling the fresh 

 dune of cows is extremely similar In chemical characters to that existing in the soluble products from the 

 n ,sses And -onir extract, obtained bv Sinclair from the dung of sheep and of deer, which had been 

 feeding upon the /.Mium perenne, Dactylis glomerata, and ZWfolium repens, had qualities so analogous 

 to those of the extractive matters obtained from the leaves of the grasses, that they might be mistaken 

 ,,r each other The extract of the dung, after being kept for some weeks, had stdl the- odour of hay 

 Suspecting that some undigested grass might have remained in the dung, which might have furnished 

 mu dee and sugar, as well as bitter extract, I examined the soluble matter very carefully tor these sub- 

 stances It tUdnot yield an atom of sugar, and scarcely a sensible quantity of mucilage.' Sinclair, in 

 comparing the quantities of soluble matter afforded by the mixed leaves of the £ohum perenne, ^actylis 

 glomerata, and Wfulium repens, and that obtained from the dung of cattle fed upon them, found then 



rf ^ol e ^ r °cmth°K * facts it appears probable that the bitter extract, though soluble in a large quantity 

 Of water, is very little nutritive ; but probably it serves the purpose of preventing, to a certain extent, the 

 fermentation of the other vegetable matters, or in modifying or assisting the function ot digestion, and 

 may thus be of considerable u»e in forming a constituent part of the food ot animals. A small quantity ot 

 bitter extract and saline matter is probably all that is needed ; and beyond this quantity the soluble mat- 

 ters must be more nutritive in proportion as they contain more albumen, sugar, and mucilage, and less 

 nutritive in proportion as they contain other substances 



57''-, la com* arm- the composition of the soluble products afforded by dtfferent crops from the same 

 grass Sir H Daw found, in all the trials, the largest quantity of truly nutritive matter in the crop cut 

 when' the seed was ripe, and least bitter extract and saline matter; most extract and sa hue matter in the 

 autumnal crop ; and most saccharine matter, in proportion to the other ingredients, in the crop cut at the 



5726 Th^ereater proportion of leaves in the spring, and particularly in thelate autumnal crop accounts 

 for the difference in the quantity of extract ; and the inferiority of the comparative quantity of sugar in 

 the summer crop probably depends upon the agency of light, which tends always in plants to convert sac. 

 cbarine matter into mucilage or starch. Amongst the soluble matters afforded by the different grasses, 

 that of the Elvmus arenarius (Jig. 711. a) was remarkable for the quantity of saccharine matter it con. 

 tained amounting to more than one third of its weight. The soluble matters trom the different species 

 of FesAca in general, afforded more bitter extractive matter, than those from the different species ot /\.a. 



afforded bitter extract, and a peculiar substance having an acrid taste, more soluble in alcohol than in 

 water Ml the soluble extracts of those grasses, that are most liked by cattle, have either a saline or 

 Bubacid taste • that of the //ulcus lanatus is similar in taste to gum arabic. Probably the Holcus lanatus, 

 which is so common a grass in meadows, might be made palatable to cattle by being sprinkled over with 



salt 



5727 No difference was found in the nutritive produce of the crops of the different grasses cut at the same 

 teuton which would render it possible to establish a scale of their nutritive powers; but probably the 

 soluble matters of the aftermath crop are always from one sixth to one third less nutritive, than those 

 from the flower or seed crop. In the aftermath the extractive and saline matters are certainly usually in 

 excess • but the aftermath hay mixed with summer hay, particularly that in which the fox-tail and soft 

 grassos'are abundant, would produce an excellent food. 



57"s Anthroxunthum odordtum K. H. — The proportional value which the grass, at the time of flowering, 

 bears to that al the tune the seed is ripe, is as + to 13. The proportional value which the grass of the 

 lattermath bears to that at the tune the seed is ripe, is nearly as 9 to 13. 



5729 HoVctM odoratua Host, G. A. — The proportional value which the grass, at the time of flowering, 

 bears to that at the time the seed is ripe, is as 17 to 21. The grass of the lattermath crop, and 

 that of the crop at the time' of flowering, taking the whole quantity, and their relative proportions of 

 nutritive matter, are in value nearly as 6 to 10: the value of the grass, at the time the seed is ripe, 

 exceeds that of the lattermath in proportion as 21 to 17. Though this is one of the earliest of 

 the Bo&ering grasses, it is tender, and the produce in the spring is inconsiderable. If, however, the 

 quantity of nutritive matter which it affords be compared with that of any of those species which flower 

 nearly at the Bame time, it will be found greatly superior. It sends forth but a small number of flower- 

 stalks' which are of a slender structure compared to the size of the leaves. This will account, in a great 

 measure, lor the equal quantities of nutritive matter afforded by the grass at the time of flowering, and the 

 lattermath. , ... 



Cuiiosi-rus c , ri-lcits E. I!. NcvAVia cu-rllca E. of P. 1070.1 — 1 he produce of this grass is greater 

 than its appearance would denote; the leaves seldom attain to more than four or five inches ill length, 

 and the Bower-Stalks seldom arise to more. Its growth is not rapid after being cropped, nor does it seem 

 to withstand the effects of frost, which, if it happens to be severe and early In the spring, checks it so 

 much as to prevent it from flowering for that season ; otherwise, the quantity of nutritive matter which 

 the grass affords (for the straws are very inconsiderable) would rank it as a valuable grass for permanent 



5731. Avina pvbiieent E. B. (Trislium pub&cens E. of P. 1052.) — The proportional value which the 

 grass at the time of flowering bears to that at the time the seed is ripe, is as ti to H. The proportional 

 value which the grass at the time of flowering bears to that of the lattermath, is as 6 to 8. The grass of 

 the seed-crop, and that of the lattermath, are of equal value. The downy hairs which cover the surface 

 ot the leaves of this grass, when growing on poor light soils, almost entirely disappear when it is cultivated 



j7J2. Pdfl aeridea var. prttt&nsis'E.B —If the produce of this variety be compared with that of 



