VII. On Fibre. By Martin Barry, M.D., F.R.SS. L. and E. 
Received December 3, — Read December 16, 1841. 
There is scarcely any term so generally used in the description of animal or 
vegetable tissue, as the term fibre. If this serves to show the universal presence of 
fibre, it also indicates the importance of having a correct notion of its structure. 
On this subject, however, physiologists differ widely : some believing fibre to be com- 
posed of globules, while others maintain that no globules can be discerned in it. 
My investigations have led me to adopt neither of these views. Should the obser- 
vations that I have to communicate be found deserving of attention, it will be owing 
to my having carefully examined the structure of fibre in the course of its formation, 
beginning with the very earliest stage. At this period, I had to deal with an object 
of considerable size ; the form of which, therefore, could be distinctly seen : and by 
tracing the metamorphoses of the large and parent fibre, I was enabled to see in the 
minute succeeding ones a structure, which I think would not otherwise have been 
discerned. We may hereafter see the cause of the difference in opinion regarding 
the structure of fibre. 
The present memoir, though devoted to the investigation of fibre, is in fact a con- 
tinuation of those which I have already communicated to the Society on the Corpus- 
cles of the Bloody. 
Formation of a Flat Filament within the Blood-corpuscle. — Structure of this Fila- 
ment. — Presence of a Filament having the same appearance in the Coagulum of 
Blood ; as well as in the Tissues generally, of both Animals and Plants. — This Flat 
Filament is what is usually termed a “ Fibre.” 
1. In the mature blood-corpuscle (red blood-disc), there is often to be seen a flat 
filament or band already formed within the corpuscle. In Mammalia, including 
Man (Plate V. figs. 4, 1, 2), this filament is frequently annular ; sometimes the ring 
is divided at a certain part ; and sometimes one extremity overlaps the other. In 
Birds (fig. 5.), Amphibia (figs. 8, 9, 10, 11), and Fishes (figs. 12, 13), the filament is 
of such length as to be coiled. 
2. This filament is formed of the discs contained within the blood-corpuscle. In 
Mammals, the discs entering into its formation are so few as to form a single ring ; 
whence the biconcave form of the corpuscle in this class, and the often annular form 
t Part I. Philosophical Transactions, 1840, p. 595, Part II. Philosophical Transactions, 1841, p. 201, 
Part III. Philosophical Transactions, 1841, p. 217. 
MDCCCXLJI. N 
