MUSCLES. 283 



able taste of beef-tea, exactly similar to that of the substance in- 

 to which fibrin is converted by boiling. It dissolves in all pro- 

 portions in water, and is precipitated by alcohol. Yet it com- 

 municates a yellow colour to alcohol of 0-833, which of 

 course dissolves a certain portion of it. Acetate of lead, proto- 

 chloride of tin, and nitrate of silver throw down brownish yellow 

 precipitates from its aqueous solution. It is not precipitated 

 by corrosive sublimate, and only very slightly by infusion of nut- 

 galls. 



It is to this substance that boiled and roasted-meat owe their 

 flavour. Muscular fibre and cellular substance of themselves are 

 quite insipid, and the other extractive substances have but a very 

 slight taste. Berzelius proposes to distinguish this extractive 

 matter by the name of zomidin* Its characters are still very 

 imperfectly investigated, and it is not probable that it has been 

 obtained in a state of purity. Indeed, as most animal substan- 

 ces refuse to crystallize, we have no criterion by which we can 

 judge of their purity or impurity. 



The liquor precipitated by acetate of lead gives with diacetate 

 of lead a new precipitate, which is almost colourless. If we de- 

 compose this precipitate by sulphuretted hydrogen, we obtain a 

 liquid nearly colourless, which, when evaporated, leaves a trans- 

 parent matter, similar in appearance to gum. When left to dry 

 in the open air it is easily detached from the glass vessel on 

 which it was placed. When burnt it gives out an acid smell. 

 Its taste is similar to that of gum. It softens in water before 

 dissolving^ and it dissolves in that liquid very readily. This so- 

 lution is not precipitated by acetate of lead, corrosive sublimate, 

 nor nitrate of silver. But diacetate of lead throws down a mu- 

 cous, colourless precipitate. Infusion of nut-gall renders it opal. 



The liquid, which is no longer precipitated by the diacetate of 

 lead, is colourless, provided it be deprived of all lead and filtered. 

 When evaporated over the water-bath it becomes slightly yel- 

 low,' and leaves a yellow mass, mixed with a great quantity 

 of acetates. If we digest it in absolute alcohol to get rid of 

 the acetates, a yellow matter remains having the following pro- 

 perties : It is yellowish-brown, has very little taste, and gives 

 out animal odour when burnt. It dissolves easily in water, to 

 which it communicates a yellow colour, leaving a small quan- 



* From etmft<,i y broth. 



