22 HAND-BOOK OF PHYSIOLOGY. 



Muscle-serum is acid in reaction, contains serum-albumin and several 

 other proteids as well as other bodies, among which are fats; free acids, 

 especially sarco-lactic, formic, and acetic; glucose, glycogen and inosite; 

 kreatin, hypoxanthin, or carnin, taurin, and other nitrogenous crystalline 

 bodies; many salts, of which the chief is potassium phosphate; Carbonic 

 acid, and lastly Haemoglobin, on which the color of muscles partially 

 depends. There are also traces of ferments, pepsin among others. 



Electrical Condition; Natural muscle currents. In muscles which 

 have been removed from the body, it has been found that electrical cur- 

 rents can be demonstrated for some little time, passing from point to 

 point on their surface; but as soon as the muscles die or enter into rigor 

 mortis, these currents disappear. The method of demonstration usually 



FIG. 275. Diagram of Du Bois ReymoruTs non-polarizable electrodes, a, glass tube filled with a 

 saturated solution of zinc sulphate, in the end, c, of which is china clay drawn out to a point; in the 

 solution a well amalgamated zinc rod is immersed and connected by means of the wire which passes 

 through A with the galvanometer. The remainder of the apparatus is simply for convenient applica- 

 tion. The muscle to the end of the second electrode is to the right of the figure. 



employed is as follows: The frog's muscles are most convenient for ex- 

 periment, and a muscle of regular shape, in which the fibres are parallel, 

 is selected. The ends are cut off by clean vertical cuts, and the resulting 

 piece of muscle is called a regular muscle prism. The muscle prism is in- 

 sulated, and a pair of non-polarizable electrodes connected with a very deli- 

 cate galvanometer are applied to various points of the prism, and by a de- 

 flection of the needle to a greater or less extent in one direction or another, 

 the strength and direction of the currents in the piece of muscle can be 

 estimated. It is necessary to use non-polarizable and not metallic elec- 

 trodes in this experiment, as otherwise there is no certainty that the whole 

 of the current observed is communicated from the muscle and is not 

 derived from the metallic electrodes themselves in consequence of the 

 action of the saline juices of the tissues upon them. The form of the 

 non-polarizable electrodes is a modification of Du Bois Eeymond's appa- 



