Abstract
1. Artificial insemination was performed with two series of female rabbits.
2. Females of the one series, which were inseminated without any other treatment, showed only 8.3 percent fertility.
3. Females of the other series, which were inseminated after copulation with a sterile male, showed 62.5 percent fertility.
4. Duration of pregnancy was one day longer in the latter case than in the former.
5. Thus the proof is fully established that in the rabbit in the majority of cases ovulation does not take place spontaneously, but needs the stimulus of copulation.
6. Successful results with artificial insemination in the rabbit, therefore, can be obtained with a greater degree of certainty if preceded by copulation with a sterile male.
