BBG at its clinically used concentration (0.25 mg/mL) during vitreoretinal surgery is safe and not toxic to HRPE for up to 5 min under focal illumination (1 cm) and up to 15 min under diffuse illumination (2.5 cm) from the commonly used SE. RESULTS of our study are useful in establishing safety parameters for the use of BBG dye in vitreoretinal surgery.

A method is described for the measurement of the thickness of thin films using the multiple beam interference techniques. Only simple equipment is required, but reduction of the order of interference to as low as one makes possible the measurement of average thicknesses down to 10A. Applications have been made to evaporated films of six different metals and the method appears to be useful for all stable thin films in thicknesses up to several microns. Possible errors in the method and the precautions which may be taken to avoid them are discussed.

A special specimen holder has been constructed for the evaporation of metals within an RCA–EMU electron microscope. This provides continuous observations on the growth of films of the metal. Micrographs are reproduced which illustrate the formation of films of silver, gold, and tin. The results confirm the usually accepted assumptions regarding the formation of nuclei and the growth of aggregates.

No abstract

Employing a technique, previously described, whereby evaporations are carried out within the specimen chamber of an electron microscope, continuous observations have been made on the formation of evaporated deposits of cadmium and zinc. The particles first seen appear suddenly, have a regular crystalline shape, and are often relatively large (200 Å). At first they remain regular while increasing in size, but later develop irregular spurs, secondary crystallites, or link together with their neighbors. This behavior is quite different from that of silver and gold in which the aggregates appear irregular at all stages.