182 ANIMAL AMIDES. 



was first noticed by Caventou and Bourdois, has a fine blue 

 colour. The addition of water precipitates the albumen white ; 

 but the acid still retains its blue colour. Caustic potash or soda 

 dissolves it, and the solution has the property of blackening sil- 

 ver. Coagulated albumen and fibrin possess exactly the same 

 properties. 



Uncoagulated albumen seems to possess acid characters, 

 though it does not alter the colour of vegetable blues. In the 

 serum of blood, it is combined with soda. When we add a so- 

 lution of a metallic salt to the serum of blood, and then drop in 

 as much caustic potash as will decompose the salt, the metallic 

 oxide does not precipitate, but remains in solution united to the 

 albumen. 



When to a solution of albumen we add acetic acid, and then 

 drop into it prussiate of potash, a copious white precipitate falls. 

 This is one of the most delicate tests of the presence of albumen 

 in liquid. 



Protosulphate of iron and sulphate of copper, according to 

 Schiibler, precipitate a very dilute solution of albumen ; but if 

 we increase the quantity of the metallic salt, the precipitate 

 again dissolves. 



The salts of tin, lead, bismuth, silver, and mercury, precipitate 

 albumen white. The subacetate of lead gives a precipitate with 

 a very minute quantity of albumen. Corrosive sublimate precipi- 

 tates albumen from a liquid containing only 5 ^o crth of its weight 

 of that principle. The precipitate is a compound of corrosive 

 sublimate and albumen. By this combination, the poisonous quali- 

 ties of corrosive sublimate are destroyed. Hence, the white of 

 egg constitutes the best antidote to this poison. According to 

 Orfila the albuminate of corrosive sublimate (if the term may be 

 permitted) is composed of, 



Albumen, . 62-22 or28 



Corrosive sublimate, 37 '78 or 17 



100-00 

 According to Bostock, of 



Albumen, . 88-89 or 136 = 28 x 5 nearly. 



Corrosive sublimate, 1 1 1 1 or 17 



lOO'OO 



