468 
MR. BOWMAN ON THE MINUTE STRUCTURE AND 
fasciculi are small, and more cylindrical, and the fibrillse appear larger and more 
distinct from one another than is generally the case in the other classes. Some of 
the areas are larger, more transparent, and less densely filled with dots than the 
others. In Mammalia, as already stated, the surface is generally nearly uniform, 
though often finely mottled ; but I have occasionaly met with specimens in which the 
extremities of the fibrillse were very visible. From the human subject, an example of 
this kind is selected (fig. 8.). In specimens in which the fibrillse appear separated 
from one another, no connecting material having an evident structure has been ob- 
served. The addition of acid serves materially to increase the distinctness of the 
fibrillse, an effect apparently due to its widening the interstices between them. 
Having now shown that the existence of the strise, as an independent structure, 
would entail consequences not in accordance with my observations, I pass on to an 
important circumstance corroborative of the view of their nature herein adopted, 
merely pausing to remark, that no writer who has believed the separate existence of 
the striae, has ever given, or attempted to give, a genuine representation of them 
copied from nature, detached from the structures to which they are said to be con- 
nected, and that until this be done, the proof of their existence as an element of mus- 
cular organization, must be allowed to be deficient. 
Now if it be true that these cross markings are the effect of an adaptation side to 
side of the beads of contiguous fibrillse, and that these fibrillse compose the whole 
thickness of the fasciculus, it is obvious that the strise ought to be found not at the 
surface alone, but throughout the wdiole interior of the fasciculus ; and this is rigor- 
ously the case. Owing to the transparency of the fasciculi, it is perfectly easy, 
under a high power, to bring into focus whatever portion of their interior the observer 
may choose. On bringing the surface nearest to him first into view, the points 
noticed early in this paper usually present themselves, and as the focus descends into 
the interior, the strise seem commonly to undergo a slight lateral motion, but con- 
tinue to be perfectly well defined, until at length they gradually become less clear, or 
are suddenly lost, according to the thickness of the object. The slight motion side- 
ways, which is so very generally observed, is of course merely a deception resulting 
from the strise seen in succession at any one point not being all precisely in a plane 
vertical to the observer, but slanting one way or the other from him, so that the 
focus in following the slant seems to move aside. Though I am not aware that this 
remarkable fact, of the existence of the strise throughout the fasciculus, has hitherto 
been noticed by anatomists, it appears to me not only to be solely explicable by con- 
sidering the strise merely an appearance occasioned by the lateral cohesion of a bundle 
of marked fibrillse, but also, in its turn, to be a proof amounting to demonstration, 
that such is in reality their nature. As far as my experience goes, it is uniformly to 
be observed wherever the strise are distinct, and it will be decisive in proportion to 
the transparency and bulk of the fasciculus. Moreover, if the fibrillse happen to have 
