MISCELLANY. 
319 
Artificial Marble. — M. Bouisson has taken out a patent for pre- 
paring artificial marble from gypsum, which is to be cut of the re- 
quired size, placed in a metallic trough in a furnace, and kept at the 
temperature of 90° for some time, after which a solution of alum in 
boiling water is poured upon it, and a gentle heat continued for some 
length of time, the water being renewed as it evaporates. For a 
block 6 feet long and 2 feet in the other directions, exposure for 5 
hours before the addition of alum solution, and 72 hours after, suffices 
to impregnate the plaster. The strength of the alum solution is 1 lb. 
to 6 quarts of water. It is always well to cut the plaster in the form 
required before hardening it. By introducing colouring matter into 
the solution various tints maybe obtained. — Ibid, from Journ. de Chem. 
Med. 
On the Action of Oxalic Acid upon the Blood and Dead Tissues of the 
Animal Body. By Dr. Letheby. — It has been stated by Dr. Coindet, 
Dr. Christison and others, that oxalic acid does not appear to have 
any corrosive action on the stomach like the mineral acids. Dr. 
Letheby, however, remarks that these statements are opposed to the 
observations which he has made. In every case which he had ex- 
amined of poisoning by oxalic acid, the stomach after death was 
found to be so completely corroded that it would not hold together. 
Numerous experiments were made with various animal tissues, such 
as submitting skin, stomach, intestine, muscle and tendon to the action 
of oxalic acid of different strengths. After standing about 12 or 14 
hours at a temperature of 60° F., it was found that the cellular and 
mucous tissue of each underwent either complete solution, or else was 
so softened that it broke down under the pressure of the thumb and 
fingers; the albuminous and muscular tissues were also softened, and 
looked as if they had been scalded. The solutions were then filtered 
and evaporated in a water-bath; by which means a gelatinous-looking 
mass was obtained, and the oxalic acid had so entered into combi- 
nation with the gelatine that it could not be dissolved out in its usual 
manner by the action of cold alcohol. — Chem. Gaz. 
On the Preparation of Caustic Baryta. By Dr. E. Riegel. — The re- 
duction of the carbonate of baryta with one-tenth charcoal and some 
tragacanth-mucilage, yields a baryta which constantly contains some 
charcoal, and most frequently also undecomposed carbonate of baryta. 
It may be obtained more pure by heating to redness the nitrate in a 
porcelain crucible ; but then the heat must be long applied, which ren- 
ders the preparation rather expensive. According to Vogel ; a fourth 
