In arteriosclerosis, especially the diffuse (senile) type, the blood pressure is invariably low, and may be spoken of as hypotension. The heart in such a case is small, the muscle is flabby, there is brown atrophy of the fibers, and some replacement of the muscle cells by connective tissue. The same causes which have produced general arteriosclerosis have also produced sclerosis of the coronary arteries, and probably the lessened blood supply accounts for much of the atrophy of the heart muscle. In typhoid fever the maximum blood pressure during beginning convalescence may be as low as 65 mm. Hg. I have frequently seen hypotension of 80 mm. This is common. Meningitis is the only acute infectious disease in which the blood pressure is more often high than low. This is accounted for by the increased intracranial tension. Following large hemorrhages the blood pressure is reduced. In venesection the withdrawal of blood may not affect the blood pressure. The procedure is done to relieve overdistension of the heart. In pleurisy with effusion and in pericarditis with effusion there is hypotension. Collapse, whether from poisoning by drugs or as the result of dysentery, cholera, or profuse vomiting from whatever cause, reduces the blood pressure. In cachectic states, such as cancer, the blood pressure is low. General wasting of the whole musculature includes that of the heart and the heart muscle shows the condition known as "brown atrophy." A most interesting and important condition in which hypotension occurs is pulmonary tuberculosis. Haven Emerson has recently gone over the whole subject in a careful piece of work and his summary is as follows: "Hypotension or subnormal blood pressure is universally found in advanced pulmonary tuberculosis, in which condition emaciation may play a part in its causation. Hypotension is found in almost all cases of moderately advanced tuberculosis, or in early cases in which the toxemia is marked except when arteriosclerosis, the so-called arthritic or gouty diathesis, chronic nephritis, or diabetes complicate the tuberculosis and bring about a normal pressure or a hypertension. Occasionally the period just preceding a hemoptysis or during a hemoptysis may show hypertension in a patient whose usual condition is that of hypotension. "Hypotension has been found by so many observers in early, doubtful or suspected cases with or before physical signs of the disease in the lungs, and is considered by competent clinicians so useful a differential sign between various conditions and tuberculosis, that it should be sought for as carefully as it is the custom at present to search for pulmonary signs.