106 PER CENTAGE OF AVOODY FIBRE IN PLANTS. 



I have spoken of these varieties of woody fibre as constituting a largo 

 portion of the entire mass of vegetable matter produced during tlm 

 growth of plants. That such is the case in the more gigantic vegetable 

 productions, of Avhich the great forests consist, is sufficiently evident 

 and so far the general statement is easily seen to be correct. It is alsc 

 true of the dried stalks of the grasses and the corn-growing plants, of 

 which it forms nearly one-half the weight, — but in roots and some 

 plants which are raised for food, the quantity of woody fibre, especially 

 in the earlier stages of their growth, is comparatively small.* Thus in 

 the beet root it forms only 3 per cent, of the whole weight when taken 

 from the ground. If suffered to remain in the soil till it becomes old, 

 or if the growth be very slow, the beet becomes more woody, as many 

 other roots do, and the quantity of ligneous fibre increases. 



§ 2. Starch — its constitution and properties. 



Next to woody fibre, starch is probably the most abundant product of 

 vegetation. To the agriculturist it is a substance of much more interest 

 and importance than the woody or cellular fibre, from the value it pos- 

 sesses as one of the staple ingredients in the food of man and animals — 

 and from its forming a large portion of the weight of the various grains 

 and roots which are the principal objects of the art of culture. 



1°. "When the flour of wheat, barley, oats, Indian corn, &c., is mixed 

 up into a dough with water, and this dough washed on a linen cloth 

 with pure water, a milky liquid passes through, from which, when set 

 aside, a white ])owder gradually falls. This white powder is the starch 

 of wheaten or other flour. 



2^. When the pith of the sago palm is washed, in a similar manner, 

 with water upon a fine sieve, a white powder is deposited by the milky 

 liquid which passes through. This, when collected, forced through a 

 metal sieve to granulate (or corn) it, and dried by agitation over the 

 fire, is the sago of commerce- 



* The following table shows the per centage of woody fibre contained in some cotmnop 

 «*ants in the green state, and when dried in the air, and at 212° : 



IN XHE GREEN STATE. 



Dried in the air. Dried at 212°. Woody fibre. Water, 

 percent. percent. percent, percent. 



Barley straw, ripe 50 — — — 



Oat straw, do, — 47 — — 



Maize straw, do. 24 — — .— 



Stalks oflhe field pea - ... — — 10)^ 80 



Field bean straw 51 — — — 



White turnip — — 3 92 



Common beet (beta vulgaris) - — — 3 86 



Young twigs of common furze - — — 24 50 



Rape straw, ripe — 55 12)^ 77 



Tare straw, do. 37 — — — 



Vetch plant (v. sativa) • -  42 — 10 j^ 77>i 



Do. (V. cracca) in flower — — 5X 68 



Do. (V. narbonensis) do. — — 11>^ 80 



White lupin, in flower, - - - — — 7 86 



Lucerne, in flower, .... — — 9 73 



Rye grass, do. — — 11 68 



Red clover, do. — — 7 79 



White clover, do. — — 4>^ 81 



Trefoil (medium) do. - - • — — 8^ 73 



Sainfoin (esparsette) .... — — 7 75 



Trefoil (agrarium) in flower - — — 12 68 



Do, (rubens) do. • - — — 15 60 



