Jf^ ^ ON VEGETABLE MUCILAGES. 



elementary substances, that serve to constitute the uhf. 

 verse. 



6. Lastly that nature, in its simple course, produces the 

 most various effects by tlie slightest modiiicatioas in the 

 means it employs. ' 



** IV. 



Oil Vegetahte Mucildges; by John Bostock, M. D. of 

 Liverpool. 



Vegetable nui- J|_ lYE term mucilage is employed, in rather a va^^ue man- 



cilage a vague ^,, ^ , „ ^,, i.-i-i 



jgr^, ner, to designate a class ot vegetable productions, vvliich, 



although they agree in many of their properties, are in other 

 The author's respects considerably dissimilar. My object in the follow- 

 object. jjjg course of experiments was to obtain a more accurate 



knowledge of their peculiar properties, and. to discover tests 

 by which their presence may be detected, without having re- 

 course to those methods of analysis, in which they are re- 

 solved into their component elements. 

 Solution of Gum arabic, when dissolved in water, exhibits all the 



gum arabic. properties of a vegetable mucilage in the most complete 

 form. I prepared a solution, in the proportion of ten parts 

 of water to one of gum, and to portions of this the follow^ 

 ing reagents were respectively added; in general one drachm 

 of the solution was mixed with ten drops of the reagent, ex- 

 ^ cept in the case of alcohol and the infusion of galls, when 



^ . . equal parts were employed, 1. Acetate of lead, 2. super- 

 Examined > ,.-, ^^ • /»• • -^ 

 ^iih different acetate 01 lead*, 3. mtro-muriate ot tin, 4. nitro-muriate of 



reagents, gold, -5. nitrate of mercury, 6. oxysulphate of iron, 7. sili- 



Their effects. ^'*^^^^ potash, 8. alcohol, and 9. infusion of galls. In No. 1, 

 there was a copious, dense, white precipitate. No effect 

 was produced in Nos. 2, 3, and 4. In No. 5 a white preci- 

 pitate appeared, which was dissolved by agitation, but was 

 reproduced by thcaddition of water, and in a few hours it 

 assumed a light pink colour. In No. 6 an orange coloured 

 precipitate was formed, at first in small quantity, but in 24 



• For the difference between these two salts see Nicholson's Journal, 

 XI, 7b', und Thoa.sai/> Chemistry, Hi, 2G2, (^3d Edit J 



hours 



