BIOLOGY. 285 



proof that the principle of volition, when in operation, exhausted 

 the muscular and nervous forces, and produced the condition 

 which, in common parlance, is i*ecognized as fatigue ; and that, in 

 the absence of volition, — or, what amounted to the same, nerve 

 in action, — the forces of the system were considerably increased ; 

 hence the use of sleep was obvious. The nervous system was 

 not only concerned in exhausting the muscular during the pro- 

 duction of motion, but constantly while maintaining the normal 

 position of the animal. He said that profound etherization, sleep, 

 fainting, and death, were different degrees of what might be 

 called functional neural paralysis, in contradistinction to purely 

 muscular, a form in which the special life of muscle was dimin- 

 ished or destroyed. The best condition for the exaltation of the 

 peculiar life of muscle was the absence of nerve, as then the 

 forces were not expended as fast as the chemical reactions be- 

 tween the muscular tissue and the blood led to their generation. 

 In sui^i^ort of the final proposition, many experiments were ad- 

 duced which clearly showed that the relaxed or elongated condi- 

 tion of the muscles was maintained by the blood, and that the 

 blood, under all circumstances, opposed the state of contraction 

 which it was the special function of nerve to bring about. The 

 various affections of muscular fibre, as they had been observed in 

 the author's experiments, were then described. 1. A muscle may 

 exist in the elongated or uncontracted state, with all its dynamical 

 powers perfect ; this is its normal condition, in the absence of voli- 

 tional ettbrt. 2. It may exist in this state, when deprived of all 

 dynamics, or, in other words, in the absence of irritability. Both 

 these conditions of relaxation may be associated with softness or 

 flaccidity of the muscular structure ; the former necessarily so, the 

 latter not, as the fixity of rigor may prevail. Again, a muscle 

 may exist in a state of complete contraction, both in the presence 

 and absence of its dynamics ; in a state of softness, or in a hard, 

 coagulated state. As with the state of elongation, so with that 

 of contraction, the truly dynamical state is one of softness. Prop- 

 erly speaking, irritability is no more the tendency which a muscle 

 exhibits to contract than the disposition it exhibits to elongate, sub- 

 sequently to contraction ; in fact, a comprehensive definition must 

 include both these conditions ; neither are either of these states to 

 be considered, as far as muscle alone is concerned, as conditions 

 of rest, for they are both active states, so long as the muscle is a 

 vital structure, and both inactive when the dynamics of muscle 

 are absent. The attractive state of the muscular molecules, which 

 represents contraction is the condition in which force is exhausted 

 by the apposition of unlike polarities ; while, in the state of elon- 

 gation, being that in which every molecule is opposed to every 

 other, force may be accumulated. In proportion to the amount 

 of force accumulated in the molecules will be the intensity of their 

 contractive or elongative energy, and also in the ratio of their 

 charge will be their proclivity to disturbance, or, in other words, 

 susceptibility to stimuli. The author combated the view of Dr. 

 Radcliflfe, who regarded the contraction of a muscle as taking 

 place simply on the withdrawal of some elongating force, and 



