MOVEMENTS OF VOLUNTARY MUSCLE. 
465 
conceive their form to be, further than observing that no trace of globular structure 
can be detected. Mr. Skey, however, believes the primitive fibrillae to be “ uninter- 
rupted threads or cylinders,” only “ occasionally exhibiting on their surface the 
marks or indentations corresponding to the distance between the circular striae on the 
whole fibre*;” and he supports his opinion by several considerations which demand 
a distinct examination. He says, in proof that the fibrillee receive their marks from 
the striae, “ I think the filament will present the more or less distinct appearance of 
a globular structure in proportion to the distinctness of the circular striae:” but it is 
clear this might be adduced with precisely equal force the opposite way. Mr. Skey 
argues for the cylindrical form of the fibrillee, by denying the existence of the reputed 
globules of SirE. Home and Mr. Bauer, and by proving the fibrillee to be three times 
finer than a blood-globule. Now, as to the globules of Sir E. Home, few who have 
examined the subject, and attentively perused his papers, can doubt that that physio- 
logist was deceived on this subject, since the fibre which he saw, and compared under 
the microscope with a string of blood-globules, was nearly as large as many examples 
of the primitive fasciculi, and very much greater than a primitive fibrilla, of the ex- 
istence of which he seems to have been ignorant. It is therefore erroneous to say, 
as has frequently been done, that the theory of a beaded structure of the fibrillae 
originated with, or was supported by him. He advocated the existence of a beaded 
tissue, but not such as I believe to exist in nature. To point out his fallacy, there- 
fore, is not to overturn what is here contended for. And with regard to the propor- 
tion in size which such beads or particles may chance to bear to the globules of the 
blood, it is a question long ago set at rest by Leeuwenhoek and Muys, the latter of 
whom gives accurate relative admeasurements of these parts, and points out their 
disparity. It is a point, too, which cannot determine the question, since no necessity 
has been or can be shown why the beads of muscle should conform to the size of the 
blood-globules, or even of their nuclei. But Mr. Skey’s most pointed argument is 
this : “ That in the Cod and Haddock, in which the striae are of extreme beauty and 
delicacy, the ultimate filaments present no appearance of a globular arrangement, 
but are distinctly continuous and uniform throughout their whole length.” Yet 
even granting this fact to be substantiated, it would scarcely invalidate the strength 
of the arguments above advanced, which speak to positive appearances. However, 
having been led to make the muscles of these fishes an object of special study, I am 
not able to confirm Mr. Skey’s remark, but have found their flesh to present the 
same characters with that of others of the same class, many of which have been also 
made the subject of observation, as the Skate, Whiting, Halibut, Salmon, &c. The 
most obvious microscopic characters of these seem to be the following. The primitive 
fasciculi are large and nearly transparent, so that when highly magnified their aspect 
is not unlike that of glass. This, as might be supposed, is shared with them by the 
muscle of many Crustacea. The fibrillae are in general distinguished by longitu- 
* Philosophical Transactions, 1837, p. 376. 
MDCCCXL. 3 0 
