The standard method of dealing with sensitivity of dosage-mortality data is the probit technique developed by Bliss and Fisher. This paper provides an alternative technique based on a special system for obtaining such data. It has some advantages when observations must be taken on individuals rather than groups of individuals, and it may be preferred in certain other situations. * This paper is in part an adaptation of a memorandum submitted to the Applied Mathematics Panel by the Statistical Research Group, Princeton University. The Statistical Research Group operated under a contract with the Office of Scientific Research and Development, and was directed by the Applied Mathematics Panel of the National Defense Research Committee.