212 USES OP THE DEPOSITION OF STARCH. 



little sac bursts, and its contents are set free and dissolved in the 

 water ; and this is why starch, once dissolved in hot water, can 

 never be restored to its original form. 



337. Thus, then, we may consider Starch as little else than 

 Gum, divided into minute portions, and stored up out of the 

 way of the nutrient fluid, which would otherwise dissolve it 

 whilst circulating. In all instances, the stores of this substance 

 appear destined for the nourishment of young parts ; since they 

 are found in the neighbourhood of these, and are exhausted by 

 their growth. Thus, starch forms a large part of the substance 

 of all seeds ; sometimes (as in the Corn grains) being deposited 

 around the germ of the young plant ; and in other cases (as in 

 the Pea and Bean) being included within it, forming a great 

 part of large fleshy cotyledons or seed-leaves, which first come 

 to the surface after the seed has begun to sprout, and which 

 wither in proportion as the young plant develops itself. Starch 

 is found abundantly, again, in the fleshy underground stems des- 

 tined to nourish young shoots, as the tubers of the Potato, and 

 the rhizoma of the Arrow-root ; and it has been lately pointed 

 out that, if the blossoms be pulled off the plants before opening, 

 the accumulation of starch will be much greater, in consequence 

 of the exhaustion of the store having been prevented. Starch is 

 also abundant in the fleshy roots which have to furnish nutri- 

 ment to the young stems, when they first begin to grow ; as in 

 the Briony and Elecampane. It is also found in the pith and 

 bark of many Exogens, and in the cellular tissue occupying the 

 centre of the stem of many Endogens (such as the Sago Palm), 

 where it forms a reservoir of nutriment for the young leaves. 



338. The deposite of starch generally continues to increase, so 

 long as the plant which forms it is in active vegetation. It then 

 arrives at its greatest amount, and remains the same until the 

 young parts which are to be supplied from it have begun to 

 grow ; and then it rapidly diminishes. Thus, it has been stated 

 that a hundred pounds of potatoes contain of starch, 



In August 10 Ibs. In March 17 Ibs. 



September 14^ Ibs. April 13flbs. 



November 17 Ibs. May 10 Ibs. 



