Note a — BOOK IV.
Reading edition
That the Muscles are compounded of Fibres, is visible enough. Which Fibres, the curious and ingenious Borelli saith, are cylindraceous; not hollow, but filled with a spungy, pithy Substance, after the manner of Elder, as he discovered by his Microscopes. Borel. de Mot. Animal. Part 1. These Fibres, he saith, are naturally white; but derive their Redness only from the Blood in them.
These Fibres do in every Muscle, (in the Belly at least of the Muscle,) run parallel to one another, in a neat orderly Form. But they do not at all tend the same Way, but some run aslant, some longways, &c. according to the Action or Position of each respective Muscle. The Particulars of which, and of divers other Observables in the Muscles, would, besides Figures, take up too much room in these Notes; and therefore I must refer to the Anatomists, particularly Steno, Borelli, Cowper, &c.