The effects of one or several intromissions on the appearance of a following series of copulations was studied when intervals of different lengths separated the series from the preceding intromission(s). It was found that: 1. When the isolated intromission was separated from the following series by intervals of 20, 40, 60, 120, 240 and 360 minutes, the intromission was seen to affect the series up to and including 120 minutes after is occurrence. 2. An additional number of 5, 8, 15 or 25 intromissions separated by intervals of twenty minutes raised the excitation level until a certain point. This was reached after between 5 and 8 intromissions. In one exceptional case the ejaculatory threshold was exceeded and the animal ejaculated after 26 intromissions. In the other cases ejaculation only appeared when the animal was allowed an additional number of intromissions separated by 90 second intervals. 3. Five intromissions separated by 20 minute periods raised the degree of excitation above the level attained by five intromissions separated by 60 minutes. 4. The results were interpreted as indicating an accumulation and reduction of the excitatory effects created by the intromissions.