470 
MR. BOWMAN ON THE MINUTE STRUCTURE AND 
frequently seen. An example of this from the Human subject is given in fig. 22. 
Lastly, the plates, of which the strise are the edges or sections, may be detached 
entire, as discs, presenting no evidence of being formed of segments of fibrillse. 
Fasciculi thus splitting have no longitudinal lines whatever, so intimate is the union 
of their fibrillee. The striae, on the contrary, are finely developed. Such, however, are 
not very often met with. Some examples are figured (figs. 23. 24. 25. 26. 27.), one from 
the Sprat, procured while in a recent state, and others from a Lizard which had lain 
long in spirit. In these instances, the segments of the fibrillae were united into discs 
of so compact a texture, that their surfaces presented little or no appearance of their 
component particles ; and they were, on the contrary, so transparent, that a careless 
observer might have imagined them to be mere rings. One of the most illustrative 
specimens of the lateral adhesion now spoken of, occurred in a rabbit newly born, 
which had been kept for some months in spirit. The parts being in progress of de- 
velopment, seemed to have undergone a partial natural dissection. A mass consisting 
of two or three fasciculi was lying in a curved form along the field, and presented on 
its convex border transverse series of beaded segments two or three deep, which, by 
the curve given to the part, had lost their longitudinal, but retained their lateral 
adhesion. They therefore stood out in relief, in the manner represented in the 
drawing (fig. 10.). Many segments of these outermost fibrillee are completely de- 
tached. 
From what has now been advanced, it is clear that the idea of the composition of 
the fasciculi by fibrillae requires considerable qualification. They split up, indeed, in 
general into fibrillae, but in other cases their natural cleavage is into discs, and in all 
instances these discs exist quite as unequivocally as the fibrillae themselves. In fact, 
the primitive fasciculus seems to consist of primitive component segments or particles, 
arranged so as to form, in one sense, fibrillae, and in another sense, discs ; and which 
of these two may happen to present themselves to the observer, will depend on the 
amount of adhesion, endways or sideways, existing between the segments. Generally, 
in a recent fasciculus, there are transverse striae, showing divisions into discs, and 
longitudinal striae, marking its composition by fibrillae. The reason why the trans- 
verse striae are ordinarily so much more decided, is that the fibrillae are more close 
together than the discs, and their shaded interspaces consequently narrower. The 
adhesion of the segments to one another is, in neither direction, fixed and rigid, but 
of a kind admitting, as will be afterwards seen, of those minute changes of position, 
which occur during the active state of the organ. The diversity now observed be- 
tween the longitudinal and transverse union of the segments, may bear reference to 
the difference in the range of these motions in the two directions, that in the longi- 
tudinal being the more extensive*. 
* Since writing the above I have met with the following remarkable passage in a recently published Croo- 
nian Lecture by John Hunter, which I give without comment. 
“ I do suppose that a muscular fibre is not one uniform body from end to end, but is made up of parts 
