The Mickoscope. 261 



intramuscular ends (Figs. 1 and 4) than in the body of the fiber. 

 They frequently are irregularly placed, but sometimes form distinct 

 rows (Figs. 1 and 23). In the latter case many of the nuclei are 

 elongated, and some show signs of division. Nuclei also occur in 

 clusters (Fig. 31) resembling the end-plates figured by Krause, but 

 in the tongue and oesophagus of bat and mouse fibers were found 

 on which several such clusters occur, while Krause thinks there is 

 only one end-plate to each fiber. A nucleus was always found 

 near the tip of an intramuscular end, and generally one at the 

 angle where a branch is given off. In caustic potash preparations 

 the nuclei are much more distinct than in nitric acid preparations, 

 unless the latter are stained. (See methods.) 



15. Steiations. — At the tapering end of a fiber the striations 

 generally become less marked, and beyond the last nucleus they are 

 sometimes clear (Figs. 2 and 14), sometimes indistinct (Fig. 4), and 

 sometimes there is simply a granular appearance (Figs. 7 and 11). 

 When the tendinous 'ends break up into processes the striation 

 becomes less marked, and in the fine fringed processes of tendinous 

 ends and intramuscular branches (Sec. 13) ceases altogether. 



16. Fascicules. — In studying serial sections of a portion of 

 the biceps femoris of the mouse it was found that the fascicles, 

 though changing greatly in shape as seen in Figs. 53-55, continued 

 from tendon to tendon as usually described; but both the secondary 

 fascicles, as shown by the fine lines in the same figures, and the 

 tertiary fascicles, or fascicules, as shown in Figs. 56-69, are 

 neither constant in shape, nor in position in the fascicle, nor do 

 they extend in their integrity from tendon to tendon. In tracing 

 from section to section it is seen that a fascicule becomes divided by 

 septa into two or more; these may be permanent or may disappear 

 and others appear, and that two fascicules at first separate may 

 unite. The figures show these changes more clearly than can a 

 description, while the gradual transition between two forms can 

 be only seen by close study of the sections themselves. The 

 fibers composing one of these fascicules are shown in Figs. 19-21. 



This subject of fascicules has not been investigated as fully as 

 is desirable; its special importance seems to be in connection with 

 the determination of some of the relations of fibers to each other, 

 which can only be finally settled by examining serial sections. 



17. Methods. — All important or doubtful points in connection 

 with this investigation were tested by at least two methods: 



a. Fresh muscle was dissected with needles in blood serum 

 only for the purpose of measuring the diameter of fibers. 



