lUGAR OF STARCH. g'^-'T' 



The gum was separated by boiling the sirup in a close vessel 

 Avith alcohol at 30^ [0-868.] 



The matter on which the alcohol had no action, and which The gum 

 was found in the most perfect sirup to the quantity of two 

 tenths, was very viscous. Being dried and powdered, it exhi- s;j„;]ar to gum 

 bited all the characters of guna arabic, namely, its solubility arable, 

 in cold water, forming a thick mucilage, insoluble in alcohol. 



The only character, that appears to distinguish this matter but does not 

 from gum arable, is its not forming mucons acid with nitric 7'^^^* mucous 

 acid. ^"«i- 



It has been asserted, however, that the gummy matter pre- ^he ^m said 

 cipitated from sirup of starch is a compound of starch, water, tobe^a com- 

 and sulphuric acid. poimd, 



To satisfy himself on this bead, Mr. Vogel poured a small but this dis- 

 portion of alcohol into sirup of starch. The precipitate first Proved, 

 formed was composed of sulphate of lime and gum. When 

 this was separated, he poured more alcohol into the sirup that 

 had been decanted from it. The second precipitate was 

 gammy matter, unmixed with sulphate ; its solution in water 

 was no longer rendered turbid by muriate of barytes. 



The author, however, was not content with this experiment ; Farther confir- 



for it might be objected to him, that the sulphuric acid, beinff "^^'"'.'^ °*^''* 



, . > • , , ' o containing no 



chemically combined wUh the gum, would not quit it to unite sulphuric acid. 



with the barytes. He dissolved this gum therefore in barytes 



water evaporated to dryness, and gave the mass a strong red 



heat in a platina crucible : thus the sulphric acid should 



have been set free, and no doubt would have seized on the 



barytes. Besides, this sulphate vi^ould have been decomposed 



by the carbon of the gum, and converted into a sulphuret : but 



muriatic acid poured on the calcined matter extricated nothing 



but carbonic acid gas, and not an atom of sulphuretted hidrogen 



gas that could be rendered sensible by paper impregnated with 



acetate of lead. 



Besides, the gum distilled on an open fire did not give out any 

 sulphurous acid, or sulphuretted hidrogen giis. 



It is not therefore a hydrate of starch combined with sul- Hypotheses 



phuric acid ; which affords us a fresh proof, that we must take ^P^ '" '"' }^^*' 



^ , , , r ^ ■ tily formed, 



care not to frame hypotheses before we consult experiment. 



He made the same trials with the sirup deprived of gum by „ , , . 

 ,,, , ■ r , No sulpluinc 



alcohol, which did not precipitate the muriate of barytes j but 



he 



