we shall see in its proper place. For now, it may suffice to gather this only from the evidence of the senses: that the command of the motive faculty of the soul is carried through the nerves, without which voluntary motion cannot be effected.

CHAPTER II.

On the description and use of the muscle.

JUST AS is usually done in other Physico-mathematical sciences, so we shall attempt to explain this science of the motûs animalium motion of animals from phenomena as if from foundations. And because musculi muscles are the primary organs of the motûs animalium motion of animals, we shall first examine their structure, parts, and evident operations.

PROPOSITION I.

The structure of the muscle is explained.

A musculus muscle is commonly posited as an organic part which consists of tendine tendon, membrane, flesh, veins, arteries, and nerves. A tendo tendon is for the most part found at the beginning and end of the musculi muscle, which seems to have a nervous consistency and to participate in the nature of a bone ligament. The tendinous beginning is called the caput musculi head of the muscle, the end is called the cauda tail, and the intermediate part is called its venter belly, which is filled with musculosa muscular flesh. Some think this does not properly constitute the musculum muscle, but rather makes for its convenient consistency by filling the interstices of the fibers, and by encrusting it in a certain way so that the fibers themselves are not harmed or lacerated during movement; I think this is false. Truly, inside the nervous or tendinous membrane are contained several fasciculi bundles, which have a prismatic form, hexagonal, square, or triangular. Individual prismatic bundles are formed from several filaments, or fibris tendinosis tendinous fibers, which in each prism are parallel among themselves and are bound together by a very tenacious glue, if they are not continued by terminal tendons or membranes, and sometimes they are immediately connected to bones or fleshy fibers.

Furthermore, the same bundles are somewhere invested and bound by countless transversal fibers, as is evident in a boiled muscle that has been dried shortly thereafter. These nervous fibers seem to compose certain reticular membranes together with the vasis capillaribus capillary vessels bringing blood in and carrying it away;