276 



MUSCLE-TISSUE. 



regularity in the form of granules in the light substance. The rows composed 

 of the bright substance vary greatly in their width. Sometimes a line of it 

 is as broad as the light substance ; or the shining substance may very much 

 surpass the light one in breadth ; or a broad line may be split in the center 

 by an exceedingly narrow light line. In other words, the bright substance 

 varies greatly in its amount in relation to the light substance. 



When we come to use higher powers of the microscope, we find that each 

 shining line is composed of a large number of square, cylindrical, or prism- 

 shaped pieces, which are the sarcous ele- 

 c z> ments of Bowman. (See Fig. 118.) 



We also see that the light layer between 

 the rows of sarcous elements is traversed 

 by extremely delicate grayish filaments, 

 connecting all the rows within a muscle- 

 fiber. When the sarcous elements are 

 separated, so as to render the light inter- 

 stices between them visible, we again see 

 the grayish filaments connecting the sar- 

 cous elements in a transverse direction. 

 Lastly, we see that all the interstices be- 

 tween the muscle-fibers are traversed by 

 delicate grayish threads or spokes, con- 

 necting the adjoining muscle-fibers, and 

 also connecting the sarcous elements with 

 the granules present between the fibers. 



From this it is evident that the mi- 

 nute structure of the fresh muscle of the 

 lobster is reticular. The uodulations of 

 the reticulum correspond to the sarcous 

 elements, and vary greatly in size, while 

 the rectangular connecting fibrillse always 

 are very delicate. 



All observers agree that the sarcous 

 elements are the active agents in mus- 

 cular contraction, because they are the 

 formations that change their shape and 

 place during the contraction of the muscle, 

 while the intermediate light spaces are 

 filled with a non-contractile liquid. 

 In order to bring out more perfectly the structure of muscle than could be 

 done in its natural state, I used, with success, a one-half per cent, solution of 

 chloride of gold, which is known to stain living matter violet. 



I also tried the freezing of the muscle by means of rhigoline-spray, in 

 order to cut the sections more easily and perfectly. But this changed the 

 texture, at times even completely destroying it, and I was compelled to resort 

 to other means. Here I may state that I suspect the peculiar condition of the 

 muscle discovered by Cohnheim, and previously mentioned, may have been 

 caused by freezing. I did not succeed in obtaining those peculiar fields, 

 described by him, in transverse sections of the muscle of the ox, made while 

 the tissue was slightly frozen. 



The next re-agent which I used was a one-half per cent, solution of 



FIG. 118. MUSCLE OF LOBSTER. 



A, muscle-fiber with single rows of 

 sarcous elements; _B, muscle-fiber with 

 divided rows of sarcous elements ; C, sin- 

 gle torn fibrilla, composed of divided rows 

 of sarcous elements ; D, single fibrilla 

 without distinct structure. CD, features 

 from specimens preserved in chromic 

 acid solution. Magnified 1200 diameters. 



