2 



Scientific Proceedings (6i). 



conclusions are based upon a long series of failures of ovaries to 

 mature upon cultures of treated species showing no departures, 

 and upon progenies including notable departures, the parental 

 forms of which proved to be a complex of elementary forms. 

 Satisfactory conditions were finally obtained with a Scrophularia, 

 native to the mountain tops of Arizona. Ovaries treated in 191 1 

 with a solution of one part potassium iodide to 40,000 of distilled 

 water, and the seedlings grown in 1912, included two individuals 

 unlike the parental strain. These and their progeny are unlike 

 their progenitors in the color-pattern of the flowers, the water- 

 relations of the stems, the degree of differentiation of the tissues, 

 the shape of the wings of the stems, the form and size of the 

 flowers, the growth-correlations and venation of the leaves. The 

 continuance of these features in the successive generations indi- 

 cates a permanent modification of the germ-plasm. 



Studies of the behavior of methylene blue, and other dyes, 

 in the ovaries, show that, in some plants, introduced solutions 

 may be taken up by the placenta and conducted through the 

 funicular stalk to the antipodal region of the embryo-sac, finally 

 staining the egg-cell. 



In other cases, the cells of the micropylar opening are stained, 

 and the pollen tube in passing through this might be affected, 

 and might also take up free foreign solutions in the open cavity. 

 It is evident, therefore, that in the introduction of substances 

 into such an ovary, the effect would depend upon the simpler 

 mechanical features of the operation, the stage of development 

 of the separate ovules, the progress of the advancing pollen-tubes, 

 and the varying dilution of the reagent in its diffusion through 

 many membranes. The individuals resulting from a treatment, 

 affecting one element only, would be of a hybrid nature: and 

 might be if both were affected to an unlike degree, or in an unlike 

 manner. 



Duplication of effects is therefore not to be demanded as a 

 test of such results and, if strict repetitions were obtained, the 

 implication that premutations were present would be strong. 

 The range of the departures is limited in expression by the morpho- 

 logical possibilities, but instead of being premutatory, may be 

 considered to be the result of the direct action of the reagent 



