294 
OBSERVATIONS ON COLLODION. 
According to M. Porret, it is a hypo-nitrite of oxide of 
lignin. He states that he has isolated the oxide of lignin, 
which he calls lignea, and has discovered it to be an alka- 
line base, which neutralized by hypo-nitrons acid, produces 
a substance identical with gun cotton. The discovery of 
this base, if confirmed by future investigations, will be one 
of the most interesting of modern times, and may throw 
new light upon some of the phenomena of vegetable growth 
and decay. 
Having already extended this essay beyond the limit 
intended, I shall pass rapidly over a consideration of some 
of the 
Uses of Collodion. 
In addition to the treatment of wounds and the appli- 
cation of bandages, for which it was at first principally 
recommended, it has since been applied with success to the 
treatment of burns, the worst cases of which will frequently 
recover with a single application of the solution, so com- 
pletely and permanently is the surface protected from irri- 
tating causes. Superficial sores and abrasions of the skin 
are cured by painting them over with the solution. It 
gives great relief in tetter and various other skin diseases, 
especially when attended with violent itching. Prof. Simp- 
son, of Edinburgh, recommends it for sore nipples, which it 
completely protects without interfering with the sucking of 
the infant. It is also found useful in the dressing of ulcers 
and of varicose veins, and in a variety of other surgical 
cases. In France, it is used to apply dressings of gold- 
beater's skin ; and above all, as a substitute for dextrine in 
permanent splints, which, by its use, they are able to 
apply over a less extended surface without diminishing the 
strength and permanence of the dressing. 
M. Soubeiran suggests its employment to render fabrics, 
particularly silk, impermeable to moisture, at the same time 
that they preserve unimpaired their color and softness. Of 
