'We must attend to the appearances of the eyes in sleep as presented from below; for if a portion of the white be seen between the closing eyelids, and if this be not connected with diarrhœa or severe purging, it is a very bad and mortal symptom.' In this, the last Aphorism which we shall quote, we see the Hippocratic physician actually making his observations. Now during sleep the eyeball is turned upward, so that if the eye be then opened and examined only the white is seen. In the later stages of all wasting and chronic diseases the eyelids tend not to be closed during sleep. Such patients, as is well known, often die with the eyes open and sometimes exhibiting only the whites. But the Hippocratic physician was not content to make only passive observation; he also took active measures to elicit the 'physical signs'. In modern times a large, perhaps the chief, task of the student of medicine is to acquire a knowledge of these so-called physical signs of disease, the tradition of which has been gradually rebuilt during the last three centuries. Among the most important measures in which he learns to acquire facility is that of auscultation. This useful process has come specially into vogue since the invention of the stethoscope in 1819 by Laennec, who derived valuable hints for it from the Hippocratic writings. Auscultation is several times mentioned and described by the Hippocratic physicians, who used the direct method of listening and not the mediate method devised by Laennec. There are, however, certain cases in which the modern physician still finds the older non-instrumental Hippocratic method superior. In the Hippocratic work περι νουσων {peri nousôn}, _On diseases_, we read of a case with fluid in the pleura that 'you will place the patient on a seat which does not move, an assistant will hold him by the shoulders, and you will shake him, applying the ear to the chest, so as to recognize on which side the sign occurs'. This sign is still used by physicians and is known as _Hippocratic succussion_. In another passage in the same work the symptoms of pleurisy are described and 'a creak like that of leather may be heard'. This is the well known _pleuritic rub_ which the physician is accustomed to seek in such cases, and of which the creak of leather is an excellent representation.