Abstract
In a recent publication on the cyclic variations of the vascular architecture of the uterus of the guinea-pig (1940) we recorded that antimesometric hypersemia is a regular and essential characteristic of the uterine changes which occur during heat, and commented on its significance as a factor influencing antimesometric implantation in this animal.A natural sequel to this work was to acquire additional evidence for our conclusions by the experimental production of antimesometric hyperæmia in the uterus of the spayed guinea-pig following treatment by injection of ovarian hormones; such evidence to be of value demands that the antimesometric hyperæmia so produced should be comparable to that of normal heat.