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Selected Articles. 
a very pungent smell of another kind. To verify the nature 
of these volatile principles, I collected the vapours with the 
greatest care in a diluted solution of nitrate of silver ; white 
flakes were formed, which when collected on a watch glass, 
washed with alcohol and water, gave out on the addition of 
hydrochloric acid, an unequivocal smell of cyanogen. There 
exists then, in the juice of the manioc, either hydrocyanic 
acid, or a principle capable of giving birth to it. After this 
trial, the fumes continuing very pungent but not acting on the 
salt of silver, I received them in pure water, which soon ac- 
quired a marked acidity. 
Wishing to ascertain the nature of this acid, and to prove 
whether it was not constituted of formic acid, originating 
either from the hydrocyanic acid or from a peculiar cyanic 
radical preexisting in the juice, I evaporated to dryness the 
acid liquid, previously neutralized with caustic soda ; the salt 
which resulted, heated in a small tube with deutoxide of mer- 
cury, did not present the marked character of the formiates ; 
namely, the formation of metallic mercury and carbonic acid: 
But when treated with sulphuric acid this salt produced pun- 
gent fumes of acetic acid. It is therefore this acid that exists 
in the juice examined ; it may perhaps have resulted from the 
alteration of saccharine principles during the time the juice 
remained in the bottle. 
The substance remaining in the retort after the above ope- 
ration, had acquired a brown colour, it was not exempt from 
acid properties, and its bitter taste indicated the presence of 
an osmazomic principle. I evaporated it very cautiously 
over a water bath, to the consistence of a syrup ; during this 
evaporation an odour of acetic acid was very perceptible. 
The syrup when cold became solid, the mass was placed on 
a cloth, drained, pressed and washed with alcohol : the re- 
sult was a whitish deposit A A. 
The drainings and washings again concentrated, were bit- 
ter, very acrid and irritated the throat very powerfully ; their 
osmazomic odour was more marked. Finally, on the ad- 
dition of a little yeast, a slight fermentation was produced, 
after the acid had been completely neutralized. Hence, it 
