484 
MR. BOWMAN ON THE MINUTE STRUCTURE AND 
the position of one of them ; and nothing is more probable than that where such an 
appearance is not due to violence in manipulation, it may have led to the error of 
supposing the fasciculi to be compounded of smaller bundles of fibrillse, as Muys 
regarded it, or of strands, or flattened sets of them, according to the views of a later 
writer*. It is owing to their extreme tenuity, and the interfering presence of the 
transverse strice, that in the ordinary state, the corpuscles are concealed, and it is by 
the augmented transparency of the fasciculi, and the more or less complete removal 
of the strise, that they are so easily brought into view by acids. And yet there is in 
this some other principle at work ; for brine and the alkalies weaken the strise and 
remove the opacity of the fasciculi, sometimes without materially serving to display 
the corpuscles. Figs. 48. 49. are taken from a specimen which has been kept some 
time in spirit, and which when first immersed did not display a single corpuscle. 
This fluid has not only rendered them more opake, but has imparted to them a 
brown colour. In general, however, muscle that has been kept long in alcohol, shows 
no corpuscles. 
It is now well known through the researches of Valentin and Schwann, that the 
fasciculi of voluntary muscle, in the earliest stage of their development, consist of a 
series of nucleated cells, and that the nuclei continue visible during the period of foetal 
growth, while those changes are in progress, that terminate in the formation of the 
transverse strise. They have been supposed to be then absorbed, and it is certain that 
they do disappear, but I have found that they are only obscured by the growing strise 
that surround them, and that they are capable of being rendered evident by the same 
means which have been already shown to discover the corpuscles in the adult. These 
nuclei of the sarcogenic cells present the identical characters of the corpuscles of 
adult muscle, and that they are both the same structure, may be regarded as proved 
by their being met with at every intervening period without any intermission. In con- 
firmation of this view, it is worthy of remark, that the arrangement of the corpuscles 
in the adult corresponds with their particular variety of disposition in the developing 
muscle of the same animal. In the larvse of several insects, in which both perfect 
and imperfect fasciculi may be examined at the same time, the row of central cor- 
puscles is equally well marked in both when properly prepared. 
In an early stage of their development, the primitive fasciculi are often narrow 
flattened bands, and present bulgings at irregular distances, which depend on the 
existence of these bodies. It is interesting to notice how closely, in this state, 
they resemble in form, size, and structure, the adult condition of the muscle of 
organic life, which has for the first time been correctly represented and described, 
though in brief terms, by Dr. Baly, the able translator of Muller’s Physiology. This 
is a fact which may hereafter prove important in the history of organic development. 
The similitude may be seen by a reference to figs. 56. 60. 66, where both kinds of 
fibre are delineated. The corpuscles of organic muscle are brought much more com- 
* Skey, Philosophical Transactions, 1837, p. 374. 
