x CONTENTS. 



[•a<;k 



§ 57. Chemistry of living muscle ; muscle-plasma, muscle-clot, and muscle- 

 serum, myoglobulin, histo-hsematin 89 



§ 58. Acid reaction of rigid muscle ; development of carbonic acid in rigor 



mortis 90 



§ 59. Other constituents of muscle 92 



§ 60. Chemical changes during contraction ; development of carbonic acid 



and acid reaction 94 



§ 61. Summary of the chemistry of muscle 95 



Thermal Changes. 



§ 62. Heat given out during a contraction. Comparison of muscle with a 



steam-engine 95 



Electrical Changes. 



§ 63. Non-polarizable electrodes. Muscle currents ; their distribution and 



nature 97 



§ 64. Negative variation of the muscle current ; currents of action. The 



rheoscopic frog 102 



The Changes in a Nerve during the passage of a Nervous Impulse. 



§ 65. The changes constituting what is called a nervous impulse propa- 

 gated along the nerve 104 



§ 66. The chemistry of a nerve ; cholesterin, lecithin, cerebrin, protagon 105 



§ 67. The nervous impulse ; the electrical changes accompanying it. These 



changes travel in both directions along the nerve .... 106 



§ 68. Summary of the changes occurring in a muscle and nerve as the 



result of stimulation 108 



SECTION III. 



The Nature of the Changes through which an Electric Current 

 is able to generate a nervous impulse. 



Action of the Constant Current. 



§69. Action of the constant current ; making and breaking contractions. 110 

 § 70. Electrotonus. Effect of the constant current on the irritability of 



the nerve. Katelectrotonus. Anelectrotonus .... 112 



§ 71. Electrotonic currents 114 



§ 72. Relation of electrotonus to nervous impulses, and to the effects of 



the constant current 116 



§73. Action of the constant current on muscle 118 



