428 Correspondence of J. Nickles. 
In 1880 he endeavored to take account of the changing odors exhaled 
by the woad vats during evaporation, if possible to define exactly the 
kind of odor vp manners to each condition of the vat. He reached no 
positive results although he detected in the dye stuff bath five perfectly 
distinct odors; the odor 0 ammonia, a sulphurous odor, a metallic odor, 
an aromatic odor, clinging for many months to the woolen stufis which 
had passed through the woad vat, oa lastly, the odor of a volatile acid 
analogous to that of animal matters in dec ——— ition. M. Chevr eul hoped 
1st, an ammoniacal odor —e blue a reddened test paper. 2d, a feeble 
butyric odor, 3d, a heavy odor which is familiar in the ‘trying out’ of 
suet or lard. No specific vai exists then in cancers, since the three odors 
recognized coexist in non-cancerous matters which the disease alters. 
smell of a due probably to a compound am 
To all these odors he adds what he ealls the 1 stale-nauseous (fade nau- 
seabonde) which appears in well-water that has stood some days in a 
vessel in which have been placed egg shells impregnated with neinagth 
[We may be permitted to-add to these interesting facts some others 
which we submit to the distinguished author of the chromatic ere and 
poocarpe on the fatty bodies. 
orous substance can be neutralized or destroyed by another 
odorant ike _ are others destitute of odor which by union produce 
odorant substan 
(To this prise of odorless ence belong O, 8, Se, Te, C, H, As, Az, 
and we might add P, which is oderless unless combined. 
2. Likewise there are odorless bodice which have become odorant by 
union with others endowed with odor, 
It is thus with oxalic, malic, butyric, sabretin: citric, sorbic (the act 
recently discovered by Hoffmann), boric, silicic acids, all odorless, wich 
"ea Tt is necessary also to rn ah bodies having an odor proper, 
that is, an odor which exists when they form compounds with other 
bodies (for example, arsenic). The arsenical odor is in AsH®, a 
AsBr®, and in the cacody] series. Tin is another example. The ¢ odor 
in charactesin large number of stannic = rian 
SNH,, SCi, = are a more or 
a mee 
