MUSCLES. 277 



tate fell has a deep red-colour like that of venous blood. At 

 134, the greatest part of the matter which it holds in solution 

 coagulates, and if we keep it for half an hour at that tempera- 

 ture we obtain a colourless cake. At 144 another coagulum 

 falls, having a reddish gray colour ; but the colour of the liquid 

 from which it fell still continues unaltered. At a higher tem- 

 perature the colouring matter coagulates ; but its quantity is 

 very small compared to the preceding deposits. These different 

 precipitates indicate albumen, probably derived partly from the 

 blood circulating in the muscle, and partly from the nervous fi- 

 lament which it contains. The coagulating temperature is lower 

 than that of albumen in the serum of the blood. But that may 

 depend upon the acid present, or upon its state of dilution or 

 concentration. 



The colourless coagulated albumen reddens litmus-paper, and 

 this property cannot be removed by washing. When dried its 

 colour becomes deeper, and at last almost quite black. Boil- 

 ing alcohol extracts from it a little fatty and a little animal 

 matter, which Berzelius considers as a combination of albu- 

 men with an acid. When long digested with water over 

 calcareous spar in powder a little lactate of lime is form- 

 ed. The liquid assumes a yellow colour, but holds in solu- 

 tion only a minute quantity of animal matter. This shows 

 that the precipitate from the liquid of muscle by heat is not ca- 

 sein. It dissolves readily in carbonate of potash, and the solu- 

 tion has all the characters of a solution of albumen. 



2. Lactic acid. If we filter the liquor from which the albu- 

 men has been separated by heat, and evaporate it to dryness, it 

 leaves a yellowish brown extract, more than the half of which is dis- 

 solved by alcohol of thespecific gravity 0-833. When thealcoholic 

 solution is evaporated to dryness there remains an extractiform 

 mass, mixed with crystals of common salt, which has a strongly 

 acid reaction ; but leaves when burnt some alkaline carbonate. 

 Hence- it follows that the matter contained a combustible acid, 

 partly free and partly combined with potash. If we mix the 

 alcoholic solution with a solution of tartaric acid in alcohol, there 

 separate bitartrates of potash and soda and tartrate of lime, and 

 there remains in solution in the liquid, besides tartaric acid and 

 muriatic acid, the combustible acid. If we digest the liquor with 

 carbonate of lead in fine powder till a portion of the lead re- 

 mains in solution the tartrate and chloride of lead precipitate. If 



