ON THE STRUCTURE OF MUSCULAR FIBRE. 257 



but at one end of the cell, and are so arranged that pairs of 

 cells have the nuclei in contiguous ends ; so that the nucleus 

 of one cell is very near that of the other. When in the 

 muscular fibre a sufficient number of the corresponding cells 

 have been preserved to enable the point to be noticed, it is 

 found that the arrangement of nuclei in contiguous cells is 

 the same as in tendon. This peculiar arrangement of the 

 nuclei is shown at a in fig. 9. 



The square cells are sufiiciently broad to cover several 

 primary bundles, and from the position in which 1 have 

 found them I believe that they invest the secondary bundles. 

 In their form and arrangement I find an analogy much 

 strengthened Avhich I formerly pointed out between the 

 secondary bundles in a muscular fibre and the bundles of 

 tendon which are invested by the cells described by Ranvier. 



On the surface of some of the fibres remnants of the sarco- 

 lemma are visible, distinguished by large rounded nuclei, 

 larger than any of the nuclei observed in the fibre. In one 

 preparation I found the sarcolemma almost entire. It is 

 represented in figs. 13 and 14, as seen by the No. 3 and 

 No. T objectives of Hartnack. I was at first in doubt 

 whether the appearance shown was not that of a part of the 

 perimysium internum, but I decided in favour of its being the 

 sarcolemma on account of its resistance, freedom from folds 

 or wrinkles, and from a peculiar and distinctive aspect 

 which I find it difficult to describe more closely. The sar- 

 colemma, as seen in the drawing, shows the size of the 

 original fibre. It contains, however, only a part of the 

 fibre, the other parts having been probably extracted 

 in the process of teasing. Be that as it may, this appearance, 

 which I have only observed in one of the preparations, is 

 sufficiently interesting to be reproduced, and I have there- 

 fore shown it as seen by a low and a higher magnifying 

 power. 



When these fibres were observed in 1874 they showed, 

 more or less distinctly, the ordinary transverse markings. 

 After maceration every trace of transverse marking had 

 disappeared, and although the easy dissection of the fibres 

 would have afibrded a favorable opportunity of observing 

 the minute network I had isolated by other methods if it had 

 survived, there was none of it visible. I am disposed to 

 attribute the remarkable change by which the fibre could be 

 divided into the bundles which compose it partly to the 

 softening of the sarcolemma, but partly also, and perhaps 

 chiefly, to the destruction by prolonged maceration in 

 glycerine of this transverse network, and I am compelled 



VOL. XVI. NEW SER. B 



