98 Dr. Prout on the ultimate Composition 



proof of the correctness of Lagrange's solution that Mr. He- 

 rapath employs to establish the truth of his own. 

 I am, Gentlemen, 



Your obedient servant, 

 4, Pancras-Lane. F. R. S. 



XVII. On the ultimate Composition of simple Alimentary Sub- 

 stances ; with some preliminary Remarks on the Analysis of 

 organized Bodies in general. By William Prout, M.D. 

 F.R.S. 



[Concluded from page 40.] 



Of the Saccharine principle. 



T N the following observations, the word Sugar, is used in its 

 •*■ ordinary acceptation; but the extended sense in which 

 the term saccharine principle is employed, requires a few re- 

 marks. 



Messrs. Gay Lussac and Thenard were induced to con- 

 clude, from their experiments on organized products, that 

 when the hydrogen and oxygen of a substance exist in it in 

 the proportions in which they form water, the substance is 

 neither acid nor alkaline, as in sugar, starch, gum, &c. ; that 

 when the oxygen exceeds this proportion, the substance pos- 

 sesses acid properties ; that when it is less, an oily or resinous 

 character*. These conclusions are true to a certain extent, 

 but by no means universally so, as will be shown hereafter. 

 I shall however adopt this general distribution of organized 

 substances so far, as to confine my attention at present to those 

 substances in which the first peculiarity above mentioned 

 exists ; and as sugar, on account of its crystalline form, ap- 

 pears to constitute the most perfect and definite of these sub- 

 stances, I have thought it best entitled to give a name to the 

 whole class, or family, and hence have included, under the 

 term saccharine principle, all those substances, whatever their 

 sensible properties may be, into the composition of which the 

 hydrogen and oxygen enter in the proportions in which they 

 form water. Now it will be found, that the substances thus 

 constituted may generally be employed as aliments ; and as 

 they are chiefly derived from the vegetable kingdom, they 

 may be considered as representing vegetable aliments, pro- 

 perly so called ; hence, saccharine principle and vegetable ali- 

 ment may be regarded as synonymous terms, and they will be 

 so employed throughout the present inquiry. 



* Recherches P/iysico-chimiques, ii. 321. 



As 



