218 E. A. Schäfer, 



the shrinking which is caused by the reagent. Consequently when 

 isolated they would look like little more than a thick interrupted or 

 jointed line, which is in my experience, the appearance which these 

 separated elements most commonly exhibit (Fig. 23). In these I have 

 not succeeded, even in preparations made by the alcohol-gold method, 

 in detecting longitudinal striation. Considering, however, their extreme 

 tenuity, their rod -like shape, and the manner in which in their coagu- 

 lated form they refract the light, it is quite possible to understand 

 that even if they in reality have a longitudinally striated structure, 

 it might still be impossible to detect this. I have myself been unsuc- 

 cessful in proving such longitudinal striation of the muscle-columns of 

 the leg-muscles in the isolated columns viewed longitudinally, and 

 I am of opinion that in most, if not in all cases, the isolated elements 

 which have been described as fibrils by other authors are neither 

 more nor less than fine sarcostyles. *) Nevertheless I do not hesitate 

 to express the belief from analogy with the wing-sarcostyles that the 

 muscle-columns of the ordinary muscles are constituted (at least, as 

 regards their sarcous elements) similarly to the sarcostyles of the 

 wing-muscles; that is that they are perforated by longitudinal tubules. 

 I would admit that the tubular constitution of the sarcostyles of ordinary 

 muscle, in most cases, evades observation, but it can nevertheless be 

 made out, to some extent, in the transverse section of the leg-muscles 

 of Hydrophilus: where each area of Cohnheim, representing the section 

 of the muscle-column, itself shows a punctated character which may 

 fairly be so interpreted. 2 ) This fact taken into consideration with 

 the fact of their general similarity of structure renders it, to say the 

 least, not improbable that the two kinds of muscles are alike in 

 structure, so far as concerns their essential contractile parts, even to 

 the most minute details. 3 ) 



*) In some instances it is quite clear, both from the descriptions and figures 

 which are given of „isola' ed fibrils", that the longitudinal lines of the sarcoplasmic 

 „reticulum" have been so described. 



2 ) Compare Rollett, Wiener Denkschr. Bd. 51, Taf. 1, Fig. 3. 



8 ) Since the above was written I have succeeded in obtaining photographs of 

 transverse sections of leg-muscle, which show a tubular structure of the muscle- 

 column. 



