MUTUAL RELATIONS OF WOODY FJURK, STARCH, GUM, ETC. Ill 



cal agriculture to render it necessary to do more than thus shortly ad- 

 vert to their existence.* 



§ 5. Mutual relations of wood t/ fibre, starchy gum, and sugar. 

 It may be interesting now to consider for a moment the mutual rela- 

 tions of the several substances, woody fibre, starch, gum, and sugar — 

 above described — which occur so largely in the vegetable kingdom, and 

 are serviceable to man for so many ditferent purposes. These relations 

 will be best seen on comparing the formulas by which they are respec- 

 tively representecL Thus — 



Woody Fibre (lignin) is represented by C12 Hg O^ 

 Cellular Fibre (according to Payen) by C^a ^\q Oio * 

 Starch (dried at 212° F.) by Cia H,oOio 



Gum (any of the 3 varieties) by C12 Hio Oi 



Cane Sugar (free from water) by C12 Hio Oio* 



Grape Sugar (dried at 130° F.) by C12 H12 Oi2f 



In these forraul<E we observe — 



1°. That the e(]ivalents of the oxygen are equal to those of the hydro- 

 gen in all the formulne, and, therefore, that all these substances may be 

 supposed to consist of carbon and water. 



2°. The formulae for cellular fibre, starcli, gum, and cane sugar, are 

 identical. They consist of the same elements united together in the same 

 proportions. 



This is one of tliose facts which not only appear very remarkable to 

 the unlearned, but are scarcely capable of being clearly comprehended 

 and explained, even by those who have most profoundly studied this 

 branch of natural science. Starch and sugar — how different their 

 properties ! how unlike their uses ! how unequal their iinporlance to the 

 human race! yet they consist of the same weights of the same substances, 

 differently conjoined. The skilful architect can put together tlie same 

 proportions of the same stone and cement — and the painter can combine 

 the same colours so as to produce a thousand varied impressions on the 

 sense of sight. In the hand of Deity matter is infinitely more plastic. 

 At His bidding the same particles can unite in the same quantity so as 

 to produce the most unlike impressions — and on all our senses at once. 



3°. A knowledge of the above close relations in composition, among 

 a class of substances occurring so abundantly in the vegetable kingdom, 

 imparts a degree of simplicity to our ideas of this otherwise complicated 

 subject. It does not appear so mysterious that we should have woody 

 fibre, and starch, and gum, and sugar, occurring together in variable 

 quantities, when we know '.hat they are all made up of tJie same ma- 

 terials, in the same or nearly the same proportions — or that one of these 

 should occasionally disappear from a plant, to be replaced in whole or 

 in part by another. 



* For a list of plants from which sugar has been extracted, seej^'homeon's OrganitChemiS' 

 try (1838), p. 647. ^ 



t Crystallized cane sugar (sugar candy) loses 53 per cent, of water in favourable circum- 

 stances. This is equal to one equivalent (HO), so that if dry sugar be Ci'^Hio Oio, crystallized 

 sugar is C18 Hu Oil— or C12 Hio Oio+HO, since there is no doubt that this one equivalent of 

 the hydrogen and oxygen exists in crystallized sugar in the state of water. Tn lilce manner, 

 crystallized lioney or grape sugar— as it occurs in honey or in the dried grape— loses 9 per 

 cent, of water when heated to 250° F. This is equal to two equivalents (2HO), so that crys- 

 tallized grape sugar is represented by C12 Hu O14 or C12 Hi2 C''4+2nO. 



