450 VOLUME OF CONTEACTING MUSCLE. 



difficulty when we consider the rapidity with which interstitial nutrition 

 takes place, and the small quantity of matter to be supplied. 



We have now analyzed the phenomenon of muscular contraction, and 

 set forth the conditions on which it depends. These we may 

 ment of this here reproduce together for the more distinct continuation of 

 doctrine. ^ Q ar g umen t. The primary act is the destruction of the 

 muscular material by the agency of arterial blood; an incipient oxidation 

 setting in, the wasting particles can no longer retain the places they have 

 occupied. They have lost their hold on the particles with which they 

 were associated. At that instant molecular attraction comes into play, 

 and shortening of the fibre is the result. The wasted material is already 

 being absorbed by the venous capillaries, and already repair is taking 

 place by the introduction of new fibrinous material from the arterial 

 blood; but the renewal or repair proceeds much more slowly than the 

 removal of the waste ; the latter effect, as might be inferred from what 

 has been said under the head of absorption, occurs almost instantly, the 

 former gradually; and thus muscular contraction presents itself as a 

 composite result, depending, under normal circumstances, partly on oxi- 

 dation, partly on removal of waste, partly on repair by nutrition, yet so 

 that if any one of these conditions be interfered with it can not take place 

 at aU. 



I can not at this point avoid offering a criticism on the experiments 

 Volume of a ^7 which it has been attempted to prove that a muscle, when 



muscle after it contracts, loses none of its bulk ; the loss that does in real- 

 contraction. .. ., . . , , 



ity occur is, it is true, very minute, perhaps so minute that, in 



the coarse apparatus which has been resorted to in these experiments, it 

 Fig. 229. . would be altogether inappreciable. Such a contrivance is 

 represented in Fig. 229, in which <z, a is a wide tube for 

 containing the muscle, g; it is also to be filled with water, 

 and from its side a narrow tube, d, projects, the water 

 reaching to some such point as e. The tube, a, a, being 

 closed at both its extremities water-tight by means of corks, 

 #, <?, whenever the muscle is made to contract by an elec- 

 tric current, applied by means of the spring wires, /", f, or 

 otherwise, if enlargement occurred the water would rise at 

 0, and if diminution it would descend ; but as, upon trial, 

 it is found that no movement whatever takes place, it has 

 been inferred that the volume of the muscle remains un- 

 changed. But no compensation whatever for temperature 

 is provided ! Yet it is positively known that when a mus- 

 cle contracts it becomes warm, and, doubtless, these in- 



Volume of contract- J -/.-IT -, i i -i ^ -i , , i 



* ing muscle. struments, if delicate enough, would have led to the pre- 

 posterous conclusion that a muscle after contraction is larger than it was 



