No rules can be laid down for blood pressure in valvular heart disease. Aortic stenosis, the rarest of the valvular lesions, is practically always accompanied by high pressure picture. Mitral stenosis on the contrary usually shows a low pressure picture. Mitral insufficiency may show an exceedingly low picture or an exceedingly high picture. Aortic insufficiency also may be accompanied by a high systolic or by a normal systolic pressure. It depends on the etiology. Practically all the rheumatic cases have low pressure, the syphilitic cases have a high pressure. It is characteristic of all cases of aortic insufficiency that the diastolic pressure is low, even as low as 30 mm. The pulse pressure is invariably high. Usually there is no difficulty in determining the diastolic pressure. The intense third tone suddenly becomes dull at the point of diastolic pressure and frequently the dull sound can be distinctly heard over the artery down to the zero of the scale. If difficulty is found in reading the diastolic as the pressure is reduced, the estimation may be reversed and the pressure gradually increased from zero to the point where the dull tone suddenly becomes loud and clear. These points always coincide. =Kidney Diseases= This has already been discussed somewhat fully in Chapter III and will receive more consideration later. It might be remarked in passing that in a case of seeming coma where albumin is found in the urine but where the blood pressure is low or normal, I have found at autopsy in several cases pyonephrosis and not chronic nephritis. The blood pressure may be useful in differentiating uremic coma from the coma of pyonephrosis. Also in the cases of coma with anasarca, either the acute, subacute or chronic form the blood pressure is not raised as a rule. Other diseases of the kidney, as tuberculosis, cancer, infection with pyogenic organisms, are not accompanied with any notable changes in blood pressure. =Other Diseases, Liver, Spleen, Abdomen, etc.= Blood pressure is only of value in the above diseases in affording information concerning the state of the circulation. There is nothing characteristic about the pressure in any of these diseases. CHAPTER VI ETIOLOGY