942 Experiments and OBfervations 
‘and the remaining fluid was again evaporated till the whéle 
when cold fhot into a mafs of cryftals, leaving only a few. 
drops which refufed to cryftallize. 
One ounce of gum arabic was treated i in the rae’ man- 
‘ner; the laft cryftals obtained were mixed with an infoluble 
white powder, which was feparated by the addition of dif- 
tilled water, and was found to be oxalat of lime.—One ounce 
of gum tragacanth was alfo fubjected to the fame procefs. 
The cryftals obtained from fugar of milk by the fame pro- 
cefs were mixed with a white powder, which, being but 
little foluble in water, was readily feparated, and appeared to 
be the faccholaétic acid of Scheele. (See Phil. Mag. Vol. II. 
p- 246.) 
Honey treated in the fame manner exhibited no figns of 
faccholaétic acid. 
’ The Table fubjoined to the prefent article will fhew at 
one view the different products refulting from deftruétive 
diftillation, with their relative proportions; and likewife 
thofe obtained by the nitrous acid. 
From thefe experiments it appears that fugar confifts 
merely of carbon, hydrogen, and oxygen; that gum differs 
from: fugar, not only in containing a lefs proportion of 
oxygen, but, alfo, by its combination with lime and azot; 
and that the fugar of milk differs from both, as it contains 
“the radical of the faccholaétic acid—in other refpeéts, how- 
ever, it approaches very nearly to the nature of vegetable 
fugar. Does the milk of carnivorous and graminivorous 
animals yield the fame proportion of this acid, and is this 
fugar itfelf always of the fame nature ? 
From the well known facts refpeéting vinous fermenta- 
tion, there is now reafon to fuppofe that no fubftances but 
 thofe which confift fimply of carbon, hydrogen and oxygen 
~ are fufceptible of it ; and that an union with a fourth changes 
the nature of the Scat Sin fo much as to render this pro- 
ecfs impraCticable. To a folution of fugar digefted with 
freth 
