20b Heredity and Eugenics 



nu'iiil)er of tlic same family, Begonia, Clcome, Ahutilon, Sphaerakea, 

 and Mfiilzflia, and otiicrs were experimented upon. Witliout recourse 

 to the detail of the work it ma\' he stated that the use of raelium ] irepara- 

 tions, su,L;ar solutions (lo per cent), and solutions of calcium nitrate, 

 of distilled water, with capsules of Rai)naiiiiia udorala, and zinc sulphate 

 in a stronger solutit)n used with Oenothera hieiuiis (Fig. 71--I) was fol- 

 k)We( 1 1 )y \ery striking results. In the first-named plant, there appeared 

 in the progeny (obtained from a few capsules of one indi^^dual several 

 individuals «-hich were seen to differ notal)ly from the typt with the 

 aijpearance of the cotyledons, and, as develo[mient proceeded, it was 

 evident that a mutant had appeared following the injections and 

 nowhere else, which thus had some direct relation to the operation. 

 The characters of the newly arisen form were so strikingly aberrant 

 as to need no skill in detection (Fig. yiU). The parent was villous- 

 hairy, the mutant entirely and absolutely glabrous, the leaves of the 

 parent ha\'e an excessi\-e linear growth of the marginal portions of the 

 leaf blades and hence become tinted; the excess of .growth in the mutant 

 lies along the midrib and the margins become revolute. The leaves 

 are widely dift'erent in width, those of the mutant being mu:h narrower. 

 The parental t^pe is of a marked biennial habit and near the close of 

 the season the internodes formed are extremely short, which has the 

 result of forming a dense rosette; the mutant forms no rosette by 

 reason of the fact that the stem does not cease, or diminish its rate of 

 elongation and hence presents an elongated leafy stem, wliich con- 

 tinues to enlarge as if perennial. The first generation of the derivative 

 came to bloom; the flowers of the mutant were closely guarded and as 

 Soon as seeds were obtained they were [ilanted to obtain a second 

 generation. A few plants were obtained, which m every particular 

 ccjnformed to the new type and exhibited no return to tlie parental 

 type. 



MacDougal's iii\'estigations, wherein were produced 

 modifications that ha\'e remained stable through four or 

 more generations, in Rai)naiinia, Ccrciis, Pciistcnioii, and 

 others, show fuUy that the method employed gives detinite 

 changes in germinal constitution. 



