The Microscope. 263 



c. Dissociation in caustic potash. A muscle or limb is placed 

 as fresh as possible into 35-40 per cent, solution of caustic potash 

 (caustic potash 35 or 40 grams, water 65 or 60 cc.) for 15-30 min., 

 depending upon the amount of connective tissue present, when a few 

 fascicles are removed to a slide, dissected quickly with needles and 

 immediately covered by potassium acetate (40 grams potassium ace- 

 tate to 25 cc. of water), and mounted permanently in potassium 

 acetate or glycerine jelly. In dissociating muscles in this way, a 

 shrinkage of at least one-fourth in length occurs. 



d. For serial sections, the animal was injected from the heart 

 with fine red mass, and the muscles prepared in the usual way for 

 serial section in paraffine. 



SUMMARY OF PART II. 



In the longer muscles, which are composed chiefly of tapering 

 fibers, those from opposite tendons interdigitate or lap by each 

 other for some distance, and the tapering ends are applied to fibers 

 of full size, or more rarely to tapering ends, from the same or 

 the opposite tendon. 



Anastomoses of various forms occasionally occurred near the 

 middle of several limb muscles of the mouse, between two fibers. 

 Previously such anastomoses, occurring in limb or trunk muscles, 

 have only been described in the ocular muscles of the sheep. 



The sarcolemma, in some cases at least, sends processes to the 

 dark line (Krause's) in the light disc, as in insect muscle, and on 

 many fibers it appears to be a tubular sheath extending beyond the 

 sarcous substance proper, at both the tendinous and intramuscular 

 end. The sarcous substance ends within this tube by minute 

 unstriated processes. 



The nuclei are irregularly placed on the fiber, or occur in rows 

 or groups, but there is always one near the tip of an intramuscular 

 end, and usually one near the point where a branch is given off. 



GENERAL CONCLUSIONS. 



In general form and arrangement the muscular fibers of these 

 minute animals agree with those of man and the larger vertebrates. 



On finding spindle- form elements in the striated muscles of the 

 trunk, Biesiadecki and Herzig drew the conclusion that in form and 

 relations striated muscular fibers of the trunk show resemblance to 

 the unstriated fibers. In comparing the facts presented in this 

 paper concerning the branched form and intimate relations of the 

 fibers of skeletal muscles, with the known form and relations of 



