CAUSE OF STRIATION OF VOLUNTARY MUSCULAR TISSUE. 329 
Addendum.—An assertion has been lately made which if 
true would be entirely fatal to my views. It was, that in the 
fresh condition the fibres are cross striped, but at the same 
time their borders are quite smooth. That this is erroneous is 
easy of demonstration with any fresh fibre, but especially with 
that of an insect. It is true that often from the manipulation, 
or their own contraction, they are twisted, when the convex 
border will on a careless inspection appear as a distinct line. 
The stripes at this point are not at all distinctly seen, but yet can 
always be made out, as well as the crenulated border. Indeed, 
this has been figured by more than one observer (Krause), and 
it was in the fresh muscle of the crab that I first observed it. 
Dr. Klein informs me that there is no doubt as to the transi- 
tional stage in the contraction of a muscle described by Engel- 
mann. It will be remembered that this is intermediate between 
the contracted and relaxed part, and that here the fibre is non- 
striated. Dr. Klein from a study of one of Hnglemann’s pre- 
parations was able to give the true explanation of this. The 
part which was non-striated was perfectly smooth in outline, 
passing at either end into the striped and crenulated fibre. 
Probably the intermediate part is a piece of the fibre stretched 
by its contraction, the two ends being fixed. 
VOL. XXI.—NEW SER, ¥ 
