I have described experiments in which circulatory failure was produced by maintaining a constant traction on the liver.1 One is ordinarily prone, however, to think only of the acute effects of circulatory failure (hemoconcentration, loss of fluid, low blood pressure, rapid and thready pulse, etc.), without at the same time thinking of the chronic effects which may come after an animal has been subjected to periods of reduction of blood pressure, not to shock but to "preshock" levels. In this connection these questions present themselves: 1. What damage is done to the animal during relatively short periods of low blood pressure (50 to 60 minutes)? 2. If any damage occurs, is it reparable or irreparable? 3. What is the mechanism of the damage?
The purpose of this paper, therefore, is to present the results and interpretations of a number of experiments designed to produce chronic effects. Traction was exerted