Galen, Rhases, and Haly Abbas repeatedly inculcate that the undulatory pulse indicates an approaching crisis by a sweat. They describe it as being strong, full, soft, bounding, and unequable. According to Galen it is most commonly met with in lethargic affections, quotidian, marsh, and typhoid fevers. (De Præs. ii, 9.) It is also said to be common in sudden attacks of dropsy. (Ib.) In some instances, however, it is the precursor of some critical evacuation, such as that by the hemorrhoids, or by the bowels. (Synops. 22.) Actuarius particularly states that critical sweats are indicated by the undulatory pulse. (Meth. Med. ii, 2.) The _dicrotos_ is distinguished by a smaller pulsation suddenly succeeding to a larger one. Galen compares it to a hammer, which, when forcibly struck against the anvil, rebounds, and strikes it again. The artery in such cases is always strong and vibratory. Philaretus describes the pulsation as being hard, vehement, and rebounding. Galen says it can only occur when the powers of the system are strong, the artery hard, and the body oppressed with a redundance of humours. He repeatedly inculcates that it indicates an approaching crisis. The singular pulse called _dorcadissans_, which we have translated _goat-leap_, is said by Galen to occur most frequently in affections of the heart and inflammations of the parts within the chest. (De Prognos. ii, 8.) It is the same as the pulse now called _jerking_, which the best authorities agree to be characteristic of pericarditis. In such cases, Hope says, the pulse is “full, hard, _jerking_, and often with a thrill.” (Diseases of the Heart, p. 99.) We suspect the modern term _jerking_, although perfectly intelligible to one experienced in the art of feeling pulses with discrimination, will be found fully as difficult to define as the _dorcadissans_ of the ancients. The _vermicular_ appears to have been the same as that which is now sometimes denominated _creeping_. In fact, Galen derives its name from its resemblance to the motion of a creature _creeping_. (Synops. 22.) It is said by the ancient authorities to occur in cases of sudden prostration of the vital powers, produced by inordinate evacuations, such as hemorrhage, cholera, diarrhœa, and the like. (De Prognos. Puls. ii.) The pulse called _innuens et circumnuens_, is said to occur only in cases of extreme debility and danger, more especially when attended with a great chill. It is connected, says Galen, with idiosyncrasy. (De Præs. ii, 11.) Is it the same as the pulse now named _flickering_?