A quantitative Study of Variation, Natural and Induced, etc. 185 
The mutant produced seeds in 1905 which when planted reproduced 
the characters of the parent within the limits of fluctuating variability. 
In succeeding crops the plants breed true even when growing unco- 
vered with branches interlocking with O. dzennis. Either the two 
types do not cross or the derivative is dominant. 
Dr. MacDougal also used an evening primrose from Patagonia, 
Raimannia odorata, with decisive results. Identical mutations were 
produced by several different means: two mutations from an ovary 
treated with a ten per cent solution of sugar, ten from an ovary 
treated with calcium nitrate 1/;999, and one from an ovary that had 
been subjected to the influence of the radium pencil. These mutations 
could be easily detected as soon as the cotyledons had become fully 
expanded. The following changes were noted. The leaves of the 
parental form were villous hairy, those of the mutant were entirely 
glabrous. The blades of the parental form become fluted, while those 
of the mutant receive the extra growth in the midrib and the margins 
become resolute. The leaves of the mutant are narrower than those 
of the parental form, and whereas the parental form is of biennial 
habit the mutant is inclined to be perennial. These characters were 
irreversible and fully transmissible in successive generations. The 
following year capsules treated with zinc sulfate 1/s999 produced the 
same mutant, as did distilled water (subject ofcourse to the impurities 
of the still). 
MacDougal next made injections on several species growing na- 
turally in the vicinity of the desert laboratory of the Carnegie 
Institution. These species included Cereus, Mentzelia, Argemone, 
Nicotinia, Escholtzia, Penstemon, and nine species of the Genera 
Opuntia, and the chemicals used included calcium nitrate, potassium 
iodide, zinc sulfate, and methyl-blue in various proportions from 
1/559 to 4/59000- Many plants, presumably from many or all of these 
treatments were under observation at the time of the last report. 
Decisive results with Penstemon Wrightii are reported. Of eighty 
plants from injected ovaries of Penstemon sixty bloomed, of which 
twenty were distinctly different from the parental form and in these 
twenty were eight distinct types. Several different injections were 
concerned in the production of these eight new types. “The revolution 
of the corolla segments, the absence of the stiff clump of trichomes 
from the lower lip, increase in viscidity, mottling of the flower, and 
adhesion of leaf bases resulting in prefoliation, are some of the 
distinguishing characteristics of the new forms.’’ Of these characters, 
