Memoirs: A Critical Study of the Facts of Artificial Fertilization and Normal Fertilization

Abstract

1. The theory of artificial parthenogenesis put forward by Loeb meets with considerable difficulties when applied to the facts of normal and hybrid fertilization. The theory of fertilization put forward by F. R. Lillie does not appear to be applicable to the facts of artificial parthenogenesis. 2. The facts of normal fertilization appear to indicate that the action of the spermatozoon on the egg is essentially of a physical nature. 3. Evidence is advanced in favour of the view that the activation of an unfertilized egg by a spermatozoon is due to the electro-motive force set up when the two gametes come into contact. The inert egg is activated by the spermatozoon in the same way as any other resting cell is activated when in intimate contact with an active neighbour. 4. After activation normal development only occurs if two asters are present in the egg. Under normal circumstances the second aster arises in the egg in conjunction with the male pro-nucleus ; in artificially activated eggs the second aster arises when the egg is treated with hypertonic solutions. 5. In the case of the echinoderm egg the formation of the fertilization membrane is discussed. One essential step in the activation of these eggs is the removal of a continuous lipoid film from the surface of the unfertilized egg. 6. The view is expressed that the only essential effect of egg-secretions on spermatozoa is the capacity of these substances, in certain cases, of increasing the activity of the male gametes.