246 Experiments on Urine. 
when the quantity of faccharine matter is but fmall, that 
the extraét obtained by careful evaporation fhould be treated 
with twice its weight of nitrous acid, and the whole reduced 
by evaporation to a very fmall compafs : when this has be- 
eome cold, the cryftals formed fhould be carefully exa- 
mined. If we perceive nothing but fmall. cubes or rhom- 
boids, we may be certain that no oxalic acid has been pro- 
duced; but if, along with thefe, we fhould obferve flender 
needles or prifms, thefe fhould be carefully feparated, dried 
on blotting-paper, and thrown into lime water: if a pre- 
cipitate is formed, it muft either be from phofphoric or 
oxalic 
and of nearly the confiftence, fmell, and appearance of treacle, Treating 
fome of this extraét with the nitrous acid, he procured the faccharine or 
oxalic acid; and with a fimaller portion of the acid it produced a fub- 
ftance, which, in refemblance and fmell, could not be diftinguifhed from 
honey.’’,_ In another cafe 36 oz. of diabetic urine yielded 3 oz..1 dr. 
10 gr. of refiduum, apparently more faccharine than the above, but having 
the other refemblances. Treating it with the nitrous acid it gave the fame 
refult. A quantity of the fame refiduum was expofed to heat in a retort : 
the firft product was evidently acid, but on the addition of potafh the 
fmell of ammonia could be perceiyed—the laft matter was manifeftly al- 
kaline, and mixed with a little empyreumatic oil. The ammonia did not 
come over in a difengaged form until the bottom of the retort became red. 
hot, and the quantity on the whole was very fmall. 
“In order to afcertain how far the faccharine matter produced in dia- 
betes refembled that fecreted in the breafts of animals, the following 
experiments were made by Mr. Cruickfhan‘ : 
“© Two drachms of cryftallifed fugar of milk were treated with 12 dr. 
of the concentrated nitrous acid, diluted with one oz. of water: after prq- 
per evaporation the liquor was fuffered to cool, when a mafs of cryftals, . 
mixed with a white powder, was depofited : thefe being feparated and 
_ dried on blotting paper, amounted to 58 gr.; about 6 dr. of hot diftilled 
water were then added, upon which tle cryftals, confifting of oxalic acid, 
were diffolved, and the white powder fell to the bottom. The clear liquor 
being decanted, the remainder was thrown into a filter, and by this means 
the powder obtained in a feparate ftate, which when dried on. blorting- 
paper amounted to Io grains. This was found to have all the properties 
of faceholaétic acid, as defcribed by Scheele, 
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