The death-knell to the theory of the personal immortality of the human soul, as ordinarily enunciated, was rung in 1875 by the German biologist, Hertzig, when he succeeded in bringing the living ovum into the presence of the ciliated sperm-cells under the microscope, while in the field of a lens of sufficient power to enable him to see clearly what took place. It is sufficient for our purpose to state that the minute the spermatozoon had pierced the cell wall of the egg-cell, the new individual of that species came into existence, and had, potentially, all of the life-possibilities, or was, in fact, as much alive as it would have been if this had happened under conditions which would have been favorable to its further development. The fact that the fertilized egg-cell immediately forms a mucous sheath the moment that its nucleus coalesces with that of the spermatozoon to prevent the further entrance of other spermatozoa, has done much to give rise and impetus to the theory that each cell has a soul, and that when these two nuclei completely fuse together, the resulting cytula, or fertilized ovum or stem-cell, has a soul peculiarly its own; which is made up in much the same way as two corresponding magnetic fields which are blended when two magnets are brought within the territory of each other's influence and unite to form a resultant field. That each of the sexual una-cells is distinguished by a form of sensation and motion of its own, and that this is true throughout the whole animal world, has given peculiar significance to these empirical facts of conception; as these will at once offer an explanation of the mysterious influence of heredity, such as was never possible heretofore. That each human individual has a beginning of existence with the coalescing of the nuclei of the parent cells, just as he has an end of existence with the violation of the integrity of his physical body, whether after the lapsing of one second or one century, must, to anyone who has observed biological phenomena like the above, be perfectly clear.