458 MOVEMENTS. 



nature of all the proximate principles that exist in the mus- 

 cular substance. The most important of these is musculine. 

 This resembles the fibrin of the blood, but presents certain 

 points of difference in its behavior to reagents, by which it 

 may be readily distinguished. One of its peculiar properties 

 is that it is dissolved at an ordinary temperature by a mix- 

 ture of one part of hydrochloric acid and ten of water. 



The muscular substance is permeated by a fluid, called 

 the muscular juice, which contains a peculiar coagulable 

 principle called myosine. 



Combined with the organic principles, we find a great 

 variety of mineral salts in the muscular substance, that can- 

 not be separated without incineration. Certain excrementi- 

 tious matters have also been found in the muscles ; and 

 probably nearly all of those eliminated by the kidneys exist 

 here, though they are taken up by the blood as fast as they 

 are produced, and are consequently detected with difficulty. 

 The muscles also contain inosite, inosic acid, lactic acid, and 

 certain other acids of fatty origin. During life the muscular 

 fluid is slightly alkaline, but it becomes acid soon after death. 

 The muscle itself, during contraction, has an acid reaction. 1 

 According to Gavarret, the muscular juice is alkaline or 

 neutral after moderate exercise, as well as during complete 

 repose ; but ne states that when a muscle is made to un- 

 dergo excessive exercise, the lactic acid exists in greater 

 quantity, and the reaction becomes acid. 3 



Physiological Properties of the Muscles. 



The general properties of the striated muscles, as distin- 

 guished from all other tissues except the involuntary muscles, 

 are as follows : 1. elasticity ; 2. tonicity ; 3. sensibility of a 

 peculiar kind ; 4. contractility, or irritability. These are all 

 necessary to the physiological action of the muscles. Their 



1 BUDGE, Lehrbuch derspecieV.cn Physiologic des Memchen, Leipzig, 1862, S. 534. 



2 GAVARRET, Les phenomenes physiques de la vie, Paris, 1869, p. 125. 



