446 MANNER OF CONTRACTION. 



Balanced state necessary consequence, that disintegration being brought 

 of a muscle a bout by the oxidizing agency of arterial blood. It must, 



through waste J i i 



and repair. however, be borne in mind that this waste is masked by its 

 incessant repair, and that its condition at any moment of its action repre- 

 sents the actual balancing at that instant of the waste and repair re- 

 spectively ; and since the repair does not proceed with the same rapidity 

 as the destruction, it needs must follow that, sooner or later, a point will 

 be arrived at when there is an absolute necessity for repose to give to 

 the renovating processes the opportunity or time for effecting* a complete 

 restoration. 



Accepting, therefore, the fact that a fibre can not contract without loss 

 Manner in ^ * ts substance, an ^ regarding that loss as the cause and the 

 which contrac- contraction as the effect, it is plain that whatever influence 

 ccurs ' can accomplish an oxidation will produce a shortening of the 

 fibre. Perhaps it may be that the nerve tubule does it by occasioning a 

 rise* of temperature; perhaps it may be, if nerves do not end in loops, 

 but in denuded points, by the current escaping into the muscle from 

 those points, and occasioning such an allotropic change in the contents 

 of the muscle cells as enables the blood to destroy them, in the manner 

 set forth in Chapter X. With such theories we need not now embar- 

 rass ourselves, but confine our attention to the result with which we are 

 concerned, that is to say, the destruction of the material contained in the 

 muscle cells, which destruction is practically brought about by the ac- 

 cess of arterial blood. When this takes place, the cell affected under- 

 goes an actual diminution of size, through loss of part of its contained 

 material, its longer axis shortening from no other cause than the cohe- 

 sion of its included granules thus suddenly brought into play. The cell 

 which we have under consideration, like an entire muscular fasciculus, 

 Restoration of P ossesses no power of active dilatation, and so remains with- 

 the contracted out change until it is stretched by similar contractions tak- 

 ing place in the components of other and perhaps distant 

 antagonist muscles. Coincident, however, with this destruction of its 

 interior substance, and loss of its prolate form, is the act of repair, the 

 nucleus of the cell reproducing other granules from materials furnished 

 by the blood ; for the arterial capillaries not only bring the means of 

 oxidation, but they bring the plastic elements of nutrition, and so per- 

 mit the cell to recover its dimensions, and to be stretched to its orig- 

 inal shape by the contraction of antagonist fibres. The destruction was 

 almost instantaneous ; the repair is an affair of a little longer time, and 

 thus, while one part is resting, other portions of the muscular mass take 

 up the action in succession, one after another contracting. Such is the 

 first series of changes ; let us now examine the second. 



For, as the result of that first stage, there has been a liberation of prod- 



