Microphotoelectric plethysmography using a rabbit ear chamber

The total and segmental microphotoelectric plethysmographs (—m; MPPG) were developed by using CdS photoconductive cells and rabbit ear chambers. The former were obtained from a whole micro-circulatory unit and the latter from segmental vessels in the microcirculation of which images were projected on a focusing glass. Both record the dynamic behaviors of the microcirculation continuously and quantitatively, and permit microscopic observations. The total and segmental MPPGs reflect various fluctuations of vasomotion and of blood flow in the microcirculation. In the microcirculatory blood flow, rhythmic fluctuations of 4–8, 8–12, and 0.5 or fewer counts/min were distinctly noticed in addition to the basic rhythm of 1–3 counts/min.

agrR wave; &szligbeta;R wave; ggrR wave; omegaR wave; rhythmic fluctuation in the microcirculation

Submitted on April 29, 1964

Isoprene and Rubber. XIII. The Constitution of Rubber

It is of special interest in connection with the structure of rubber as well as that of all natural products of high molecular weight that two basically different viewpoints exist, and that both have been supported by experimental investigations. Both these concepts concerning the constitution of rubber are discussed in the following paper. I. The Constitution of Rubber According to Pummerer Pummerer defends the correctness of the basic concept of Harries “that a parent rubber hydrocarbon exists, which as a result of some condition tends to association and as a result gives the impression of a rubber of gigantic molecular weight. The question of whether this point of view is justified is of the greatest interest to colloid chemistry. The tendency to association may depend upon various factors, for example, upon the state of saturation, upon the size, or even upon the form of the molecules”. Pummerer expresses similar ideas, as does Bergmann about the constitution of polysaccharides and albumins. This concept is supported by Pummerer by important experiments.