salt solutions used to cause eggs to develop, presumably preventing the increase in permeability usually caused by the salt solution.
The use of fish eggs in settling this question presented itself to the writer. It was found that the eggs of the pike will develop in distilled water and are practically impermeable to salts—that is to say, that the salts which they contain diffuse out of them only in such small quantities as to render detection almost impossible even with as sensitive an instrument as the nephelometer. It was found, further, that pure solutions of sodium nitrate increased the permeability of the eggs to chlorides (since the chlorides diffused rapidly from the eggs). The use of anesthetics prevented the effect of nitrates on the permeability of the eggs, so that the chlorides failed to diffuse.
It is thus evident that the problem of parthenogenesis is closely interwoven with fundamental problems of physiology—stimulation, oxidation and anesthesia; and that the final elucidation of parthenogenesis and fertilization must wait on the solution of these other problems. On the other hand, the systematic study of parthenogenesis has already shed much light on general physiology, and progress will be more certain if all of these problems be kept before the mind of the investigator.
- Science, 1914, Vol. 40, p. 214.