Upon this point the attention of the reader should be specially directed. What authorities support this conclusion? Only a few need be named, for there would appear to be no difference of opinion among physiologists regarding the fact. Sir Thomas Lauder Brunton, one of the leading medical writers in England, in a contribution to the latest edition of the "Encyclopaedia Britannica," tells us: "IRRITATION OF SENSORY NERVES tends to cause contraction of the bloodvessels, AND TO RAISE THE BLOOD-PRESSURE."[1] [1] Enc. Brit., Art. "Therapeutics," p. 800. Dr. Isaac Ott, an American physiologist of distinction, states in a description of certain vivisections made by him: "IT IS A WELL-KNOWN FACT THAT IRRITATION OF A SENSORY NERVE causes an excitation of the vasomotor centre, WHICH IS INDEXED BY A RISE OF PRESSURE.... As indirect irritation ALWAYS PRODUCES A RISE OF PRESSURE, the sensory nerves and the conductors of their impressions up to the (spinal) cord are not paralyzed."[2] [2] Ott, "On Physiological Action of Thebain," pp. 11-12. Dr. Leonard Hill, in an article contributed to Schafer's "Textbook of Physiology" upon the circulation of the blood, says: "Arterial pressure is affected reflexly BY STIMULATION OF ANY SENSORY NERVE IN THE BODY.... The usual result of stimulating a sensory nerve is A REFLEX RISE OF ARTERIAL PRESSURE."[3] [3] Schafer's "Textbook of Physiology," vol. ii., pp. 166-167. The writer goes on to explain that when the tone of the system in weakened "after prolonged experiment OR DURING THE ADMINISTRATION OF CHLOROFORM AND CHLORAL," then a fall of pressure may occur. This phenomenon was known to physiologists many years ago. For instance, Dr. J. C. Dalton, professor of physiology at the College of Physicians and Surgeons, in his well-known textbook on physiology, says that the most frequent instance of reflex constriction of arteries is that "which follows irritation of the central extremity of a sensitive nerve." "This effect has been observed by many experimenters, and is regarded as nearly invariable. Galvanization of the central extremity of the sciatic nerve causes general constriction of the bloodvessels throughout other parts of the body, INDICATED BY INCREASED ARTERIAL PRESSURE. A similar result is produced by the irritation of ... other sensitive nerves, or nerve roots."[1] [1] Dalton's "Physiology," pp. 507-508. And, referring to another experimenter, Dr. Crile, puts the case clearly: "PAIN INCREASES (BLOOD)-PRESSURE. In four cases of trauma (injury), a rise of 20 to 40 was noted upon pressure upon a nerve. Even in a healthy person, pinching the integument was noted increase the pressure."[2] [2] Crile "On Blood-Pressure," p. 341.