STUDIES ON THE ABSORPTION, DISTRIBUTION AND ELIMINATION OF ALCOHOL VI. THE PRINCIPLES GOVERNING THE CONCENTRATION OF ALCOHOL IN THE BLOOD AND THE CONCENTRATION CAUSING RESPIRATORY FAILURE

It has long been recognized that the severity of the physiological effects following the ingestion of alcohol is related to the concentration of alcohol developed in the blood. This relation is the basis of the “blood test ” now widely used in the medico-legal diagnosis of intoxication. In employing this test it is also recognized that there may be individual differences in the degree of intoxication corresponding to a given concentration of alcohol as deter-mined in the blood. These differences are usually attributed to individual variations in susceptibility and tolerance. Less well recognized is the fact that during the period in which alcohol is being absorbed, there may also be considerable difference in the concentra-tions of alcohol in the blood, not only as between arterial and venous blood but also as between the venous blood from different sources. Furthermore, none of these concentrations may represent the concentration of alcohol in the brain and it is the concentration in the brain which determines the physiological effects. These points are sometimes of great importance. It is true that most medico-legal tests are made several hours after the alcohol is ingested and after absorption is virtually complete. By this time the concentrations of alcohol in blood from all sources are in sufficient agreement for practical purposes. On the other hand, failure to appreciate the differences occurring before ab-sorption and distribution are complete has led to serious errors in many experimental studies as we have previously pointed out (1). Unless allow-ance is made for these differences, it is impossible to correlate concentration and physiological effect at all accurately. This point is especially important in determining, as here, the concentration causing death. Failure of respira-tion can be produced in acute alcohol poisoning only while absorption is still taking place