PART ONE,

ON THE EXTERNAL MOTIONS OF ANIMALS AND THEIR FORCES.

CHAPTER I.

In order to discourse methodically on the local motion of animals, all species of motions that belong to animals must be recounted. Firstly, it is known that an animal migrates from one place to another by transferring its entire mass from one position to another. If such transit happens upon the ground, it is called gressus walking/stepping; if its transport is effected in water, it is called natatus swimming; but if its translation occurs through the liquid region of the air, it is called volatus flight. Also to be considered are the various motions and transpositions of the parts of the animal, which are either externæ external, such as those of the hand, legs, head, etc., or internæ internal, such as those of the viscera, heart, arteries, veins, or muscles, bones, and other parts of this kind. Or, finally, there are the flows and motions of fluids through the cavities and vessels of the animal, such as blood and other humors. Therefore, to inquire into the faculties, instruments, and artifices by which Nature