title: Parameters of the menstrual cycle: A reply.
abstract: Abstract   In a set of two papers, one of them published in this journal in July 1965, W. H. James defends the menstrual statistics of E. J. Farris and his co-workers and exploits these data to propose a new formula of calendar rhythm that allegedly provides maximum protection for a given amount of abstinence.   The present paper argues that Farris's data are open to a suspicion of serious bias. James's estimates ofvarious parameters of the menstrual cycle are questioned mainly on grounds of deficient data. However, it is concluded that his methods of estimation will prove useful in future analyses of menstrual variation.
authors.forename: R G
authors.initials: RG
authors.lastname: Potter