Dr Martin Barry on Fibre. 395 
ment which produces in the entire object a flattened form, and gives it a 
grooved appearance. It is, in fact, the structure which, for want of a 
better term, he has called a flat filament. The edge of this filament pre- 
sents what, at first sight, seem like segments, but which, in reality, are 
the consecutive curves of a spiral thread. A transverse seetion of such 
an object is rudely represented by the figure 8. This is also precisely 
the appearance presented by the minutest filament, generally termed 
Fibre: and the author particularly refers to the oblique direction of the 
line separating the apparent segments in the smaller filament, in connec- 
tion with the oblique direction of the spaces between the curves of the 
spiral threads in the larger one. 
The spiral form, which has heretofore seemed wanting, or nearly so, 
in animal tissues, is then shewn to be as general in animals as in plants. 
Nervous tissue, muscle, minute bloodvessels, and the crystalline lens, 
afford instances in proof of this. And if the author’s view of identity in 
structure between the larger and the smaller filaments be correct, it fol- 
lows that spirals are much more general in plants themselves than has 
been hitherto supposed ; spirals would thus appear, in fact, to be univer- 
sal as a fibrous structure. 
The tendency to the spiral form manifests itself very early. Of this 
the most important instance is afforded by the corpuscle of the blood, as 
above described. The author has also obtained an interesting proof of 
it in cartilage-from the ear of a rabbit, where the nucleus, lying loose in 
its cell, resembled a ball of twine, being composed at its outer part of a 
coiled filament, which it was giving off to weave the cell-wall ;—this 
cell-wall being no other than the last-formed portion of what is termed 
the intercellular substance—the essential part of cartilage. These nuclei 
in cartilage, as well as those in other tissues, there is ground for believ- 
ing to be descended, by fissiparous generation, from the nuclei of blood- 
corpuscles. 
The author then describes the mode of origin of the flat filament or 
fibre, and its reproduction in various animal and vegetable tissues, which 
he enumerates. He conceives that each filament is a compound body 
which enlarges, and, from analogy, may contain the elements of future 
structures, formed by division and subdivision, to which no limits can be 
assigned. 
He then traces the formation of muscle out of cells, which, according 
to his observations, are derived from corpuscles of the blood, to the state 
where there exists what is denominated the fibril, In this process, there 
are to be observed the formation of a second order of tubes within the 
original tube; a peculiarly regular arrangement of discs within these 
second tubes ; the formation, first of rings and then of spirals, out of 
discs so arranged ; the interlacing of the spirals; and the origin, in the 
space circumscribed by these, of spirals having a minuter size; which in 
their turn surround others still more minute; and so on. The outer 
spirals enter for the most part into the formation of the investing mem- 
