This paper describes a sensitive, automatic recording microspectrophotometer capable of measuring the light absorption of substances present at ``enzyme'' concentrations in a single living cell. Modified dynode-feedback and measuring circuits have been especially adapted for measurement of small photocurrents at relatively high signal-to-noise ratios. The application of the instrument to observations of the mitochondrial aggregate (Nebenkern) of the grasshopper spermatid is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.