The tendons are the principal parts of the muscle; and that part thereof, as before observed, which is fastened in the bones, namely, at the head and tail of the muscle, and is the chord, as it were, by which the limb is brought into motion. A tendon is a hard, substantial, flexible, and elastic body, which, at the head of the muscle, is very compact; but as it enters the muscle, spreads its fibres over the whole body, gathers again at the tail, in as compact a manner as it began, and continues in this chord-like texture till it fastens itself at its appropriated place.[7] Footnote 7: It must be observed however, that tendons take on many various forms, as different as the muscles; which would be too tedious here to particularize. The tendons and ligaments are of equal substance, and differ in nothing but their various uses; namely, the ligaments to connect the articulation; and the tendons, or the ends of the muscles, to give motion. The muscles are a composition of the tendinous fibres, plentifully intermixed with small ramifications of blood vessels; all which compose the fleshy part thereof. Hence, the tendons being white and hard, the muscles gradually grow softer and redder in the middle of them; and they verge gradually to become tendinous at the tail, the same as the head. Hence, from the close texture of the tendons, they are very painful when wounded, or otherwise hurt; but as the muscles are softer and more pliable, their wounds and other accidents are of less consequence, and not so dangerous as the former. The number of muscles are undetermined, for though the principal muscles are so distinct that they cannot be mistaken as to their form and use, yet there is so great a number of small ones, or so many of the great ones capable of being subdivided again, that anatomists have not, as yet, agreed about their number. ------------------------------------------- SECT. VIII. _Of the Urinary Organs and Genital Parts._ The _kidnies_, the _ureters_, the _bladder_, and the _urethra_, are the principal urinary organs. The kidnies receive two arteries called the _emulgent arteries_, from the great arterial trunk, called _aorta_, before described; they each send also two veins back again, accompanying the arteries to the _vena cava_. Whilst the blood is circulated in the kidnies, the urine is secreted in many small quantities, and carried from each kidney by a tendinous tube, the bigness generally of a small goose quill, called the _ureter_ to the bladder. The _ureters_ enter the bladder between its _lamillas_, so as not to admit of a return. Hence, a bladder in its natural position is both wind and water tight, and if reversed, is neither.