On the structure of cross-striated muscle. 185 



And if this contractile cell -protoplasm offers no such structure, the 

 argument, which would affirm that the muscular substance must have 

 this structure on account of its origin from, and essential identity with 

 protoplasm, necessarily falls through l ). 



The battle as to the real structure of muscle must be fought, 

 therefore, on its own merits, and is not to be settled by a priori 

 reasoning. We must, in fact, endeavour to arrive from a consider- 

 ation of the structural appearances of muscle itself, living and dead, 

 altered and unaltered, at a decision of the question whether the 

 muscular substance is a continuous whole which is pervaded by a 

 regularly meshed network, or whether it is discontinuous, that is to 

 say, columned or flbrillated. 



In stating that a decision between these two views must be made, 

 I do not wish to ignore other Aaews regarding the interpretation of 

 the structural appearances of muscle which have, from time to time, 

 been put forward. But since at the present moment the controversy 

 is practically between the two theories above mentioned, it seems 

 best to avoid burdening the subject by discussing others of less im- 

 portance, although there may be occasion briefly to refer to some of 

 them later on. 



General appearances of the ordinary muscles (leg-muscles 



of insects). 



I have already said that the appearances of muscle in the living 

 state and after the influence of reagents are admitted practically by 

 all investigators. Confining our attention for the present to the ordi- 



one into the other which would be observed if Bütschli's explanation were a valid 

 one. In the absence therefore of any evidence to the contrary, pseudopodial proto- 

 plasm must be still looked upon as devoid of structure, and since this is the most 

 actively moving part of the cell-substance, it cannot well be maintained that the 

 reticular structure is essential to amoeboid movement. 



*) The absence in the Amoeba of a reticulum which could be brought into 

 view by treatment by the acid chloride of gold method was proved by Marshall, who 

 appears to have made the experiment in the hope of finding, by a positive result, 

 support for the idea with which he started, that muscle should possess a contractile 

 reticulum corresponding with the reticulum of ordinary protoplasm. His failure to 

 obtain the expected result does not, however, appear to have led him to abandon 

 the idea which prompted the investigation. 



