The causes affecting the pulses are next to be treated of, with which is connected the prognosis from them. We shall begin with those which respect magnitude, because it is more obvious than the others. A great pulse is produced either by some urgent necessity, such as an excess of heat in the heart requiring refrigeration, and, as it were, ventilation from without; or it may arise from leanness of the body, as we shall soon show. The excess of heat is occasioned either by natural causes, such as the ages of manhood and youth, or simply a hot season, place, or a warmer temperament; or by non-natural causes, such as the air which surrounds us being hotter than common, hot baths, exercises, food, wine, heating medicines; or by preternatural causes, such as a hot intemperament, putrefaction of the fluids, passion, or the like. You may judge of these classes of pulse from the following observations. Those which are natural are permanent and not very susceptible of change, whilst the others readily change, so that often while you examine them, or generally after a very short time, they will altogether alter. A pulse also which owes its greatness to a hot bath has softness for an accompaniment; and hardness is generally combined with greatness proceeding from a hot intemperament, especially when combined with dryness of the system. Those who have undergone moderate friction or exercise have a pulse intermediate between hardness and softness; but they have the parts about the chest warmer than natural, which is the case also with those in a passion. Those that are influenced by food, the use of wine, or rage, have vehemence joined to greatness. Those who wish to conceal anger, or something which they have done without permission of the physician, (such as if a person has taken a heating medicine, and wishes to conceal it from the physician, who inquires about it while he feels the pulse,) in such persons a manifest inequality is joined to greatness. To the discovery of this state other considerations may contribute, such as the habit of the patient, as if he appeared to be fond of taking medicines, or his disposition, as if it be bad, and cunning at concealments. A pulse which is great from putrefaction of the fluids has a contraction more hasty than natural joined to its greatness. To form a great pulse, an urgent necessity is not alone sufficient; but the vital powers must also contribute, and a condition of the instrument or artery intermediate between hardness and softness. When the heat, therefore, is increased in the heart by any of the above-mentioned causes, in the first place the pulse becomes great, and, the greatness not being able to supply the want, quickness is straightway joined to it; and if that is not sufficient, density is superadded. Small, slow, and rare pulses are formed by the opposite causes. But when a change first takes place from a great, quick, and dense pulse to their