A NEW CAUSTIC, ETC. 
277 
The mucilage in manna is the same as ordinary mucilage. 
The sugar is crystallisable grape sugar. The resin and acid 
are soluble in ether. — Ibid, from Licbig's Snnalen. 
i 
ART. LXXVI. — A NEW CAUSTIC FORMED BY THE MIXTURE 
OF SAFRAN (PEROXIDE OF IRON) WITH SULPHURI 
ACID. 
Br M. Velpeau. 
During a series of experiments, to which he had for some 
time devoted himself, on the action of various powerful 
caustics, M. Velpeau at length arrived at sulphuric acid, 
solidified by safran, a combination that appeared to have 
the most happy results. To concentrate the sulphuric acid 
under the form of a ductile paste, or rather a soft pommade, 
not capable of extending beyond the limits he had traced 
out, he had to make a host of attempts and trials; it wa s 
necessary to discover a body or bodies which, combined 
with the liquid mineral, could form a concrete, without de- 
priving it of its caustic properties. Asbestos, charcoal, flour, 
and various other substances failed. At length he came to 
safran, which incorporates easily, and in sufficient quantity 
to make a pommade of a proper consistence. This substance 
being carbonized by the acid, a paste of a beautiful black 
color is the result, reminding one of China ink or dried black- 
ing. This paste is placed in a china vessel ; the surgeon 
takes it up with a spatula and spreads it over the ailing spot 
as he would soft cerate; he forms a layer from two to four 
millimetres in thickness, more or less, makes the edges round 
and circumscribes the limits to the actual seat of the dissase, 
leaving it exposed to the air for some time until it is dry- 
25 
