[15] Hertwig’s description of the method by which a piece of hydra makes a new one shows that he did not understand the kind of change that takes place in this animal.
[16] Organographic der Pflanzen, ’98.
[17] This term is used by Driesch to his Analytische Theorie.
[18] Delage, Y. La Structure du Protoplasma, etc., ’95.
[19] The dark red glass was fairly monochromatic; the dark blue let a trace of red light through.
[20] The same difference was found in this form in regard to heliotropism.
[21] Palæmon and Sicyonia.
[22] The regeneration of the lens of triton may also be affected by gravity.
[23] Driesch does not give in his paper (’99) the position of the hydroids, or the method of the experiment, but I can supply the details given above from a personal communication from Driesch.
[24] Jacobson has shown that the layer of water just above the sedimentary layer at the bottom is poor in oxygen.