MOVEMENTS OF VOLUNTARY MUSCLE. 
485 
pletely into view by treatment with acicl (figs. 65. 67.)* In conclusion, it may be 
observed, that in the course of my investigations into the minute structure of organs, 
I have noticed corpuscles of a similar character in the sarcolemma itself, in the coats 
of capillary blood-vessels, in the sheath of nerve, and in the substance of tendon, all 
of which I believe to be analogous, both in their origin and nature, with those now 
described ; that is, they are the nuclei of cells from which these several structures 
have been originally developed. It is, however, not impossible, that in all these cases, 
there maybe during development, and subsequently, a further and successive deposit 
of corpuscles, from which both growth and nutrition may take their source. In the 
case of muscle, indeed, this may be regarded as certain, since their absolute number 
is far greater in the adult than in the foetus, while their number, relatively to the 
bulk of the fasciculi, at these two epochs, remains nearly the same. 
Of the Extremities of the Primitive Fasciculi, and their union to other Structures. 
This has always been a subject of considerable interest, and an examination of it 
is necessary to complete the idea of a primitive fasciculus. I presume it to be well 
understood, that all fasciculi of voluntary muscle are fixed immediately to some tissue 
analogous to the fibrous. Such at least is the case in the higher classes, and in the 
lower it is probably universally true. The gross form under which this fibrous tissue 
is arranged, it is not my purpose to speak of, as nothing more is here intended than 
to inquire how the minute fibrils are disposed at their attachment to the fasciculi, and 
how these fasciculi terminate. The observations which follow are few in number, 
and it must be left for the future to determine how far the facts elicited are of ge- 
neral application. 
In Mammalia and Birds, it will always be found a very difficult task to detach 
from the mass a small set of tendinous fibrillse, with the primitive fasciculi belonging 
to them, in such a way as to gain an unequivocal view of their union ; and all my at- 
tempts to do this have hitherto failed. This result is to be attributed to the smallness 
of the fasciculi, and to the abundance and intricacy of the cellulo-vascular net-work 
by which they are commonly surrounded, these circumstances tending to prevent the 
disengagement of the individual fasciculi, and therefore of the minute detachment of 
tendinous fibrillse with which each is furnished. In Fish, neither of these obstacles 
occurs, and accordingly in this class the most satisfactory evidence on the subject is 
to be found. So many deceptive appearances are apt to present themselves in an in- 
vestigation of this nature, that no conclusion can be fairly drawn from any fasciculus 
not entirely isolated; for it is impossible correctly to appreciate the relations of mus- 
cular and tendinous parts when mutually intermingled. From inattention to this 
circumstance, I conceive that excellent physiologist Treviranus has fallen into the 
error of supposing the fasciculi to taper much towards their extremities, so as to be 
inserted among, and to be embraced by, the fibrils of the tendon*. In the case of 
* Beitriige zur Aufklarung der Erscheinungen und Gesetze des organischen Lebens, von G. R. Treviranus, 
Tab. VIII. Fig. 59. 
