492 Intelligence and Miscellaneous Articles. 



bulky precipitate is formed, which is to be dried by exposure to the 

 air ; and it is then a yellowish viscid mass of a peculiar animal 

 odour and a disagreeable taste. Pepsin thus obtained has an acid 

 reaction, because it always contains a small quantity of acetic acid, to 

 deprive it of which various processes were tried, and that which suc- 

 ceeded was heating it in a salt-water bath for some hours, by which 

 a white powder soluble in water and possessing no acid reaction was 

 obtained. It is to be remembered that pepsin loses some of its 

 power of assisting digestion by the action of a high temperature, but 

 as it is not at the same time altered in its chemical constitution, M. 

 Vogel employed it for analysis; the mean of several experiments gave 



Hydrogen 5*666 



Carbon 57*718 



Oxygen 16-064 



Azote 21-088 



100-536 

 M. Vogel remarks, that the results of this analysis show that pepsin 

 is not identical with modified albumen, as has been supposed ; he 

 further states that the action of pepsin in digestion may be com- 

 pared to that of disastase, which changes fecula into grape sugar, 

 without itself undergoing any alteration ; this opinion was supported 

 by the fact, that of two grains of pepsin which had acted upon dressed 

 beef so as completely to dissolve it, 1* 98 grain was recovered. 



The pepsin of the sheep possessed only in a slight degree the power 

 of favouring digestion. — Journ. de Pkarm. et de Chim., Oct. 1842. 



ACTION OF CHLORIDES ON SOME MERCURIAL COMPOUNDS. BY 

 M. MIALHE *. 

 A solution of 60 parts of common salt, and 60 of sal-ammoniac, is 

 termed by M. Mialhe the assay liquor : in this 60 parts of various 

 mercurial compounds were digested, during twenty-four hours, at 

 the temperature of the air, and in the heat of a stove ; the former 

 varying from 59° to 68° Fahr., and the latter from 104° to 122° Fahr. 



I. Protobromide of Mercury. — The alkaline chlorides behave with 

 this salt as with calomel, with this difference only, that out of the 

 contact of the air the small proportion of the bisalt of mercury which 

 is formed is, at least momentarily, bibromide and not bichloride of 

 mercury; whereas, while reacting in the presence of air, the greatest 

 proportion of the mercurial bisalt formed is bichloride. 



1st Experiment. — At the temperature of the air, corrosive subli- 

 mate produced - 6 part. 



2nd Experiment. — By the heat of a stove, corrosive sublimate pro- 

 duced 1*5 part. 



II. Protiodide of Mercury. — This is one of the mercurial salts in 

 which the solution of alkaline chlorides acts with the least intensity. 



1st Experiment. — At the temperature of the air, corrosive subli- 

 mate produced 0'5 part. 



* M. Mialhe's researches on the action of chlorides upon protochloride 

 of mercury will be found at p. 320 of the present volume. 



