MUSCLES. 505 



liquid and a solid fat (olein and palmitin). It is acid 

 from the presence -of lactic acid (?), and contains, further, 

 salts from the aqueous secretion. In sheep it consists 

 of several kinds of fat and a saponaceous compound of 

 potassium and calcium with a fatty acid. 



The perspiration is acid, and contains free acetic, 

 butyric, formic, and carbonic acids. It contains only 

 J to 2 per cent, of solid ingredients, consisting of urea, 

 undetermined animal matters, potassium and sodium 

 chlorides, and small quantities of sulphates and phos- 

 phates. Strongly smelling perspiration appears to con- 

 tain also caproic acid, and a volatile organic sulphur 

 compound. In certain diseases, as in cholera and kid- 

 ney complaints, a large increase of the normal, small 

 quantity of urea, contained in perspiration, takes place. 

 In other diseases sugar and uric acid, and under certain 

 conditions also succinic acid, have been detected in 

 perspiration. 



8. Muscles. 



The finest recognizable parts of voluntary muscles 

 are microscopical, reddish, transversely striated fibres, 

 which are united in bundles. The finest bundles are 

 inclosed in sheaths of cellular tissue, and are united 

 by cellular tissue, forming larger bundles. A large num- 

 ber of such larger bundles, bound together by a sheath 

 of cellular tissue, forms a single muscle. In the sheaths 

 is distributed a network of fine bloodvessels and 

 nerves. 



The principal ingredient of muscular tissue, con- 

 gealed after death, is a protein compound, myosin 

 (p. 491). It is not yet decided whether this substance 

 is, as such, contained in a state of solution in the liv- 

 ing muscle or, similar to blood-fibrin, is formed after 

 the cessation of life. The peculiar phenomenon of 

 rigor mortis is, however, undoubtedly caused by the 

 coagulation of the myosin, and this occurs quite inde- 

 pendently of the acid, which makes its appearance in 

 muscular tissue after death, and generally after the 

 rigidity. 

 43 



