EXPLANATION OF THE PLATES. 



PLATE XLI. 



STRUCTURE OF MUSCLE. 



Fig. 1. A portion of the surface of a striped muscle mag- 

 nified about 60 diameters, showing the distribution 

 of the blood vessels and fat globules. 



2. A fragment of unstriped muscle ; the fibres, with 



their nuclei, in one half of the figure are less dis- 

 tinct than in the other, the filaments in the second 

 half having been submitted to the action of acetic 

 acid. 670 diameters. 



3. Muscular fibrillae of the heart ; previous to the ac- 



tion of acetic acid they are observed to be trans- 

 versely striped ; this re-agent however obliterates 

 the stripes and reduces the fibrilta to the same 

 condition as those of unstriped muscle. 670 dia- 

 meters. 



4. A fragment of a muscle of the frog, showing the 



distribution of the capillary vessels and nerves ; 

 the tubules of these last are observed to terminate 

 in ganglion-like bodies situated between the mus- 

 cular fibrillae. 350 diameters. 



