CHAP. IX.] 



THE CONTRACTILE TISSUES. 



339 



The variations in the proportion of water which occur during 

 muscular contraction will be referred to in a subsequent section. 



Mineral Fresh muscle yields on ignition from 1 to 1;5 per 



Salts. cent, of mineral matters, containing as their principal 



constituent potassium and phosphoric acid. 100 parts of the mixed 

 mineral matters contain about 36 parts of phosphoric acid. There 

 are also small quantities of calcium and magnesium phosphates and 

 traces of chlorine and iron. The remarkable preponderance of 

 potassium over sodium in the ash is to be remarked. 



SUMMARY OF THE QUANTITATIVE COMPOSITION OF MUSCLE. 



la the following Table, which is quoted from Hofmann 1 , the average amounts of the 

 various constituents in 1000 of the muscles of vertebrates is given. 



SECT. 2. GENEKAL PHENOMENA OF LIVING MUSCLE. 



Muscle in a state of Rest 



We have in the previous section made ourselves acquainted with 

 the normal appearances and composition of living muscular tissue. 



1 Hofmann, Lehrbuch der Zoochcmie, p. 104. 



222 



