165 
as a result of the genetical studies of Jimson Weed (Datura 
Stramonium) that have been carried on during the past several 
years by Dr. A. F. Blakeslee, at the Station for Experimental 
Evolution (Carnegie Institution of Washington) at Cold Spring 
Harbor, L. I. The work, for the present, will be confined to ex- 
posing egg- and sperm-cells of pedigreed plants of this species to 
radium rays. The project is in continuation of experiments made 
in 1906 in which pollen-grains and egg-cells of the Evening-Prim- 
rose (Oenothera biennis) were exposed to radium rays. The ef- 
fects of those experiments appeared to be confined to the somatic 
characters of the offspring, without affecting their genetic con- 
stitution. 
Status: 
Using plants that had been inbred by selfing for nine genera- 
tions, ovules in flower-buds of different ages were exposed to the 
gamma rays given off from radium emanation contained in a 
sealed capillary glass tube. Seeds from a single capsule, so 
treated, yielded plants as follows: (a) 17.7 per cent. chromosomal 
mutants (chiefly non-disjunctional forms )—a much higher per- 
centage than has ever been obtained from untreated capsules, the 
average for over 15,000 offspring being 0.47 per cent.; (b) A 
new compound chromosomal type, called “ Nubbin”; (c) Two 
new gene mutants out of 18 individuals tested. It is believed that 
the radium rays may be considered as the chief factor in produc- 
ing most, if not all, of these three types of results. 
Plans: 
To continue and extend this work, and to make cytological 
studies of egg- and sperm-cells exposed to the radium rays. 
Personnel for Project 7: 
C. Sruart GaceER, Director (roro0- ee a oytacuse 
(1895), Sc.D. (1920); Pd.M., New York State Normal College 
(1897); Pd.D. (1901); Ph.D., Cornell (1902). Professor, bi- 
ological sciences, New York State Normal College (1897-1905) ; 
Director of laboratories, N. Y. Botanical Garden (1906-1908) ; 
Professor of botany, University of Missouri (1908-1910). 
(This project is being carried on in collaboration with A. F. 
BLAKESLEE, Member of Staff, Station for Experimental Evolu- 
tion, Cold Spring Harbor, L. I.) 
