Seminal receptacle

When spermatozoa of the most sensitive and most resistant strains were treated inside the seminal receptacles of females of a third strain, these differences disappeared clearly they resided, not in the spermatozoa or their chromosomes, but in anatomical or physiological features of the males that carried them. Differences among strains and species in response to chemical treatment have remained one of the major obstacles to estimates of genetic hazards from environmental substances. Even in the same animal, different germ cells may differ greatly in their response to a given mutagen. This was known for X-rays and now was found to apply also to mustard gas. 

---