422 ANIMAL BODY : 



slum : tannin, bichloride of mercury, and basic acetate of lead 

 cause considerable turbidity. 



The Muscles. 



Muscular fibre is chemically distinguished from the fibre of 

 cellular tissue by the circumstance that it does not yield gela- 

 tin by prolonged boiling in water, but dissolves in acetic acid, 

 from which it may be precipitated by ferrocyanide of potassium, 

 showing that it belongs to the protein-compounds. The micro- 

 scopic characters of the various species of muscular fibre have 

 been well described by Heule. 



In consequence of the difficulty that exists in separating 

 muscular fibre from cellular tissue, vessels, and nerves, it is 

 impossible to speak with certainty respecting the behaviour of 

 pure muscle towards reagents. If very small pieces of muscle 

 are freed as much as possible from fat and cellular substance, 

 and immersed in water, blood, colouring matter, and the ex- 

 tractive matter with which muscle abounds, are gradually taken 

 up, and colourless muscular fibres are left. 



Cold water and alcohol produce little effect on them, but in 

 boiling water they first contract and become firm, and subse- 

 quently soften. Concentrated acetic acid dissolves them; in the 

 dilute acid they swell and assume a transparent fibrous appear- 

 ance. The alkaline carbonates increase their firmness. Solu- 

 tions of muscular fibre in dilute acids are precipitated by 

 ferrocyanide of potassium and tannin in a precisely similar 

 manner to acid solutions of fibrin. Dried muscular fibre may 

 be easily pulverized; in that condition it resembles the whole 

 class of protein-compounds in exhibiting strong positively elec- 

 trical properties. 



On making incisions into the warm flesh of an animal just 

 killed, we obtain, by pressure, an acid fluid which rapidly coa- 

 gulates in consequence of the presence of a little fibrin : if 

 the flesh has been kept for some time the fluid obtained by 

 pressure no longer coagulates, although it exhibits an acid re- 

 action. No quantitative analysis of human flesh 1 has yet been 



1 [The following analyses of human flesh by Marchand (Lehrbuch der Physiolo- 

 gischen Chemie, p. 156) and L'Heretier (Traite de Chimie Pathologique, p. 660) have 



