CLARKE, ON STRIPED MUSCULAR FIBRE. 9 
frequently the appearance of a cell-wall, so that the body 
might be taken for a true nucleated cell, giving origin to a 
process or fibre. Such would be the case at f and g, fig. 14, 
if the lateral band were a little finer, and were joined at 
each end of the mass by another from the opposite side. I 
have examined such a multitude of specimens from embryos 
of all ages, with so much care, that I can scarcely see how 
any unbiassed and candid inquirer, who has devoted the 
same attention to the subject, can arrive at any other conclu- 
sion than the one I have just drawn. 
In the opinion of Deiters, the muscular fibre and striated 
mass is to be considered in the light of an intercellular sub- 
stance, secreted by the so-called nucleated cells. Whether it 
be a product of secretion or not, I leave out of the question ; 
but supposing these bodies to be true nucleated cells, with cell- 
walls, it is quite certain that their separate existence, as such, 
is far from being a necessary condition for the development 
(secretion) of the muscular fibres; for by the descriptions 
and figures of Dieters himself, it is shown that several of 
these cells frequently coalesce to form either a continuous 
band or tube,—in which the nuclei are disposed in linear 
series,—or an irregular mass, in which they lie without any 
order, so that in these cases the process of secretion would 
be carried on, not by separate cells, but by tubes, bands, or 
irregular masses formed by the coalescence of cells. However, 
there is little doubt that the muscular substance is the result 
of some process carried on by the nuclet themselves. Now, ac- 
cording to my own opportunities of observation, the organic 
muscular-fibre-cell is developed on the same plan as the 
striated fibre in its first stage, viz., by the formation of sar- 
cous substance around a nucleus encrusted with blastema ; 
so that the latter kind of fibre, instead of being the product of 
a nucleated cell, would appear to be itself a kind of cell- 
formation, which at first finds its prototype in the organic 
muscular-fibre-cell, and in which the investing sarcous sub- 
stance represents the cell-wall. 
