CHEMICAL SCIENCE. 245 



by the pulmonary parenchyna in most animals, and which may be 

 found free, but is usually combined with a salt of soda. Obtained in 

 the crystalline form, it is a brilliant body, strongly refracting light. It 

 does not lose its water of crystallization at a temperatue of 100 

 Centigrade ; but when heated still more, it decrepitates, melts and is 

 decomposed, giving rise to empyreumatic products. Much coal re- 

 mains, which disappears without leaving any traces of ash. It is 

 soluble in water and boiling alcohol, but not in cold alcohol or ether. 

 Its ultimate analysis exhibits definite proportions of carbon, hydro- 

 gen, oxygen, nitrogen and sulphur. It forms crystallized salts with 

 bases, and expels carbonate acid from the carbonates. The existence 

 of this substance is of high physiological interest ; for the acid thus 

 secreted by the parenchyma comes in contact with the carbonate of 

 soda of the blood, transported by the capillaries, and decomposes it, 

 uniting with the soda and setting free the carbonic acid which is 

 exhaled. The presence of a portion of this acid in the free state, in 

 the parenchyma, indicates that it is really there that it is formed, and 

 not in the blood, which is an alkaline fluid. By uniting with the soda 

 of the blood, the acid does not change the reaction of that fluid, since 

 it merely takes the place of the carbonic acid which is expelled dur- 

 ing expiration. Journ. de Chemie Medicate. 



OST CHROMIC ACID AS AN ESCHAROTIC. 



CHROMIC acid has been on the recommendation of Dr. Heller tried 

 in many cases as an escharotic, and the results thus far obtained justify 

 a further trial of it in cases in which a deeply penetrating, gradual 

 caustic, and one constant in its effect would be indicated. When 

 employed in substance, its action is exceedingly slow and gradual, 

 occupying many hours ; nevertheless in intensity it exceeds that of 

 the caustic alkalies. In extremely concentrated solution, its action is 

 less penetrating and less gradual, but at the same time, it is more con- 

 tinuous than that of all other known caustics ; on the other hand, the 

 more dilute the solution, the more transient and superficial is the 

 effect. The facility with which its action can thus be graduated ren- 

 ders it in all cases a suitable escharotic. The method of application 

 is as follows : the surrounding parts having been protected by folds of 

 lint, adhesive plaster, &c., the chromic acid is spread with a spatula on 

 the part to be cauterized, so as to form a layer scarcely a line in thick- 

 ness, which is covered with lint, kept in its place by adhesive plaster. 

 The concentrated solution may be applied by means of a glass rod, or 

 hair pencil, and the part after a few moments' exposure covered with 

 lint. If chromic acid be applied to sound parts, a moderate sensation 

 of burning commences in ten or fifteen minutes after the application, 

 increasing for three or four hours, and then diminishing for about an 

 equal space of time. Its application to ulcerated parts excites similar 

 sensations instantaneously. Undissolved chromic acid causes severer 

 and more permanent pains; these are also more violent when the 

 putis vera itself, and not morbid growths is cauterised. The pain does 



