The Osmotic Pressure of the Ions and of the Undissociated Molecules of Salts in Aqueous Solution.

To illustrate the advantages of germinating Oenothera seeds under experimental conditions over the old practice of sowing upon earth I will give the results for a problem as attacked under the old and new method. In 1914 I germinated on earth seeds from an F1 hybrid plant, 13.35ac, of the cross 0. franciscana X 0. biennis. A sowing of 819 seed-like suctures produced a culture of 402 seedlings, a germination of about0%0o. The culture was grown partly to test the inheritance of a character (red coloration of the papillae on the stems and ovaries) present in franciscana and absent in biennis. This character was fully dominant in the F1 of this cross and in its reciprocal. It seemed reasonable to expect that a proportion of the plants in the F2 generation would present the clear green stems and ovaries (recessive) of biennis, but I found no plants of this type in the culture of 1914. This winter (1915) I germinated in Petri dishes seeds from the same F1 hybrid plant, 13.35ac, and obtained 761 seedlings from about 921 seed-like structures,-a germination close to 82%. The new method'had raised the proportion of germination more than 30%0. Of the 761 seedlings I was able to bring 748 to rosettes, the 13 which died probably belonging to a small group of etiolated dwarfs difficult to grow. It becomes a matter of interest to see whether or not in this culture of 1915 a group of greenstemmed plants will appear.