The pulse is a movement of the heart and arteries, taking place by a diastole and systole. Its object is twofold; for, by the diastole, which is, as it were, an unfolding and expansion of the artery, the cold air enters, ventilating and resuscitating the animal vigour, and hence the formation of the vital spirits; and by the systole, which is, as it were, a falling down and contraction of the circumference of the artery towards the centre, the evacuation of the fuliginous superfluities is effected. The arteries themselves are oblong hollow vessels like the veins, but consist of two coats, in order to fit them for the afore-mentioned motion, and because they have to contain blood and spirits. They arise from the heart, and are distributed to all parts of the body; and, therefore, all the arteries pulsate in a similar manner, and like the heart, so that from one of them you may judge concerning all the rest. But the movement of all cannot be equally well observed; for those which are situated in parts not fleshy may be more conveniently felt, whereas those that are in fleshy parts are more indistinct. Nor is any one more conveniently situated for being felt than the one at the wrist. The first kind of pulses is in regard to the time of their motion, as observed in systole and diastole. Its differences are, the _quick_, _slow_, and _moderate_; because every body which is moved must be moved quickly, slowly, or intermediately, as to time; that is quick which is moved over a great distance in a short time; that is slow which is moved over a short distance in a long time; and that is moderate which is intermediate as to motion. The second kind of pulses is in regard to the extent of the diastole. For, since every body has three dimensions, length, breadth, and depth, and an artery is a body, it follows, that an artery must have these dimensions. When, therefore, an animal is in its natural state, you will find its arteries dilated moderately every way; but when not in its natural state, its dilatation will be deficient, or exceed according to some one of its dimensions. In calculating this, you must remember the natural state of the pulse; and if it is found to exceed in breadth, you must call it _broad_; if in length, _long_; and if in depth, _high_ or _deep_. It is clear that the opposites to these, or those that are deficient, are to be named the _narrow_, the _short_, and the _low_. And with regard to those which are altered from the natural state in all their dimensions, that which is every way diminished is called _small_, and that which is every way increased, _great_. The third kind of pulses is with regard to the tone of the vital strength. The varieties are three, the _strong_, the _weak_, and the _moderate_. The strong is that which strikes the finger of the physician strongly, and the weak, feebly and faintly; while the moderate is intermediate between them, and is held by some to be the natural one; for that the