Book Review

Das STR~MUNGSGESETZ DES BLUTKREISLACFES. By Karl Wezler and Werner Sinn. Editio Cantor Aulendorffi. Wiirttemburg, 1953, pp. 126, 36 figures.

This monograph is, in a way, the culmination of Wezler’s work in Otto Frank’s laboratory extending over 20 years. Starting from the validity of Poiseuille’s model experiments in ap- plication to peripheral circulation, the role of complicating factors such as viscosity, character of the blood suspension, pressure variability, and most important, elasticity of the arterial wall, is discussed and investigated. In spite of large differences in various perfusion preparations, the flow-pressure relationship can be expressed by a simpleexponentialequation, inwhich the functional state of the vessel is characterized by the value of the’exponent (> 1 .O contracted, < 1 dilated). The authors arrive at a single, though rather complex equation, incorporating all factors found to be of importance for the resulting peripheral blood flow. For instance, the change of the length of the vessel with blood pressure is considered in addition to changes in diameter. The equation, “the law of flow of the blood circulation”, is tested and confirmed in animal experiments (lung preparations) under various experimental conditions.

The significance of these results for the interpretation of blood flow experiments is illustrated in selected examples from the literature. It is shown, for example, that even such a competent author as H. Rein misinterpreted his experiments on the effect of atropine on coronary circulation. The application to the definition of the “total peripheral resistance” is also of interest.

The book will contribute to a more precise analysis of peripheral circulation and is recom- mended for all interested in the fundamentals of this complex field. It is, in the best sense, a continuation of 0. Frank’s work.

E. S.