This is specific to the study of empirical equations and is the first of a series of publications that seek to spread the quantitative method in studies of biology and medicine. One of their most important problems of scientific work is when you have to measure, establish and describe relationships between variables; most of the established scientific laws.

20 cases were studied typical mitral stenosis, ranked according to Dexter degrees, through the dye dilution curve in the following: circulatory times. cardiac index, central volume (pulmonary blood volume, Newman), intrathoracic volume (Hamilton), blood volume. Compared with normal values for sea level indicated by us. In parallel with the severity of the disease, circulation times were prolonged, decreased cardiac index and increased blood volume. Expressed in absolute figures, the central volume (pulmonary blood volume) increased in parallel with the severity of the disease; but expressed as a percentage of the blood volume, the increase was significant only in grade III patients, the intrathoracic volume did not change significantly. There is a statistically significant correlation between the central volume and intrathoracic volume. Our work shows that there is no systematic increase...

The dilution technique has been used for the description of the circulatory dynamics in the heart and lungs of inhabitants of sea level and high altitude. The main purpose of this study was to measure the amount of blood in the lungs of these groups of people, through the formula of Newman, to show whether the natives of high altitudes have a greater amount of blood in the lungs. The following calculations were made: circulation time, volume, heart squeezing, intralorácico blood volume (Hamilton), central volume (Newman) and total blood volume. At sea level, 20 men and 15 women were studied. In altra (4,540 mts.) 10 men who were born and still living at 4,540 m were studied. When values are corrected per square meter of body surface, no marked difference between men and women at sea level, apart from the known hematologic differences. Natives live show longer circulation times, a volume...