A method based on the familiar coupling azo dye technique has been devised for the study of enzyme distribution in thick specimens. Its application to the study of esterase distribution in whole tadpoles of Xenopus laevis is described in detail. It can also be used to show the distribution of alkaline phosphatase, both in Xenopus tadpoles and in limbs dissected from chick embryos. It has proved...

Of several chick culture methods investigated, New's technique produced the greatest percentage of normal bulboventricular loops. In embryos with two left cardiogenic areas or with two right cardiogenic areas or with the areas exchanged, the bulboventricular loop develops to the right in the cases in which there is integration. When each of the areas was permitted to be expressed without the ot...

The demonstration by Stuart-Harris that the W.S. strain of epidemic influenza virus can induce a fatal nervous disease in mice has been confirmed. In contrast, however, no previous period of adaptation to chick embryonic brain was required. By serial brain to brain passages in mice originally inoculated with the virus cultivated in the usual chick embryo culture medium a fatal disease, essentia...