94 TRANSVERSELY STRIPED MUSCULAR FIBRES. 



p. 135, and this being done, the inosic acid must be separated in 

 the manner described in vol. i, p. 222, viz. : by adding alcohol 

 to the mother-liquid of the creatine. About 5 times the volume of 

 spirit should then be added to the mother-liquid of the inosates of 

 potash and baryta, on which the fluid separates into two layers, the 

 upper one of which contains lactate, acetate and butyrate of potash 

 and creatinine. In order to separate the latter substance, we treat 

 this lighter fluid with ether, on which it again separates into two 

 layers, the upper one of which contains nearly pure creatinine, 

 which crystallises on the evaporation of the ether. The lactic 

 acid and the above-described volatile acids of the heavier layer are 

 separated according to the usual methods. In the heavier stra- 

 tum of the mother-liquid of the inosates which is formed by 

 the action of the spirit, the main contents, in addition to the extrac- 

 tive matters, are inosite and chloride of potassium. It is easy to 

 obtain evidence of the presence of creatinine in fresh muscular 

 juice by Liebig's method of boiling the solid residue of the mother- 

 liquid of the inosates in spirit of wine, and adding chloride of zinc 

 to the spirituous fluid, which causes the compound of chloride of 

 zinc and creatine to separate in a crystalline form. 



The examination of the parts which are insoluble in water does 

 not call for any additional remarks, as it has been already noticed 

 in detail in the preceding pages ; in general, however, the mode of 

 investigation corresponds with that which has been described for 

 the organic muscles. 



If we inquire whether the chemical investigations of the mus- 

 cular substance which have been hitherto made, throw any light on 

 the nature of its functions, we find that very little information has 

 been gained which can either afford support to any of the existing 

 hypotheses, or can suggest new ones. By proceeding with the 

 greatest caution by the method of induction, we arrive at the fol- 

 lowing conclusion : 



The protein-substance, which can be extracted from the mus- 

 cular fibrils by extremely dilute hydrochloric acid, is the most 

 essential element of animal motion ; it is one and the same in the 

 striped muscular fibres, in the smooth muscles, and in the tissues 

 which were formerly termed contractile. It is, however, peculiar 

 to those organs whose movements are dependent on the nervous 

 system. We are unable to explain on chemical grounds the man- 

 ner in which this substance alters its physical properties during the 

 contractions of the tissues. 



The voluntary and involuntary muscles contain moreover a 



