June, 1920] GEMETICS .'*27 



plants of the Fj generation which produced dwarf forms were Bomewhat shorter in height 

 and ear length than those which yielded normal forms. The proportion of normal forms 

 to dwarfs approached the 3: 1 ratio, showing that dwarfness in this case is recessive. In 

 every case, however, tliere were one to about three per cenl leBS dwarfs produced than 

 expected. Author ascribes this lowering of expected percentage to failure of germination 

 and use of unskilled labor. As natural crossing occasionally takes place in wheat and dwarf 

 segregates were found to hardly produce any seed or even head out, from an economic view- 

 point the writer considers risky the growing of varieties which are liable to produce dwarf 

 forms when naturally crossed. — S. Boshnakian. 



2179. PORTER, William C. Huntington's chorea; a report of a family history study made 

 in Dutchess and Putnam counties, New York. New York State IIosp. Quart. 4: 64-74. Nov., 

 1918.— This paper gives a short history of pedigree investigations into Huntington's chorea. 

 This began with Dr. Charles N. Waters, of Franklin, Delaware County, New York in 1842. 

 Continuing, Dr. Charles R. Gorman, of Pennsylvania, reported a group of cases in 1848, 

 and Dr. Irving Lyons, of Fairfield County, Connecticut, reported 3 cases in 1863. Dr. 

 George Huntington, in 1872, reported studies made by himself, his father and grandfather 

 in Easthampton, Long Island, through a period of 72 years. The author then gives a first- 

 hand pedigree study accompanied by Chart A, "The W — Family." In this family 



group 56 persons are charted, 19 of whom had Huntington's chorea and 13 of whom were still, 

 at the time of the report, below the age of 35, which is taken as the average age of incidence. 

 Chart B records 49 persons, of whom 15 had chorea and 2 were indicated as below the age of 

 incidence. Chart C records 25 members of the family-tree, of whom 7 had Huntington's 

 chorea and 9 are recorded as below the average age of incidence. — //. H. Laughlin. 



2180. Rasmuson, Hans. Zur Genetik der Blutenfarben von Tropaeolum majus. [On 

 the genetics of the flower colors of Tropaeolum majus.] [German.] Bot. Notiser 1918: 253- 

 259. Nov., 1918. — Dark yellow crossed with light yellow gave dark yellow in F x and approxi- 

 mately 3 dark yellow to 1 light yellow in F 2 . Light yellow bred true in F 3 , dark yellow gave 

 some populations containing only dark yellows and some containing approximately 3 dark 

 yellow to 1 light yellow. Red crossed with yellow gave red in Fi and approximately 3 red to 1 

 yellow in F 2 . Homozygotes were dark red and heterozygotes light red, and in each class 2 

 sub-classes existed according as red was borne on dark or light yellow base. In F 3 dark red 

 gave only dark reds, yellow gave only yellows, and light red gave approximately 3 red to 1 

 yellow. Existence of different genetic types of red is considered self-evident. On account of 

 technical difficulties only small populations were secured throughout. — R. E. Clausen. 



2181. Rasmuson, Hans. Uber eine Petunia-Kreuzung. [On a Petunia cross.] [Ger- 

 man.] Bot. Notiser 1918:287-294. 1918. — In 1915 author made several crosses between 

 forms of Petunia hybrida (the product of P. nyctagini flora Juss. X P. violacea Lindl.). One 

 of these has been followed to the F 2 generation. Pi female had almost white flowers with 

 blue throat and anthers. Pi male had violet flowers with yellow throat and anthers. Fi 

 generation produced four different types: I. Violet, blue anthers, blue throat, 15 plants; 

 II. Violet, yellow anthers, yellow throat, 15 plants; III. Dark red-violet, blue anthers, blue 

 throat, 10 plants; IV. Dark red-violet, yellow anthers, yellow throat, 2 plants. These are 

 assumed to belong to two genotypes, the first comprising types I and III, the second, types 

 II and IV, giving a segregation ratio of 25: 17 for blue, as contrasted with yellow, anthers and 

 throat, thus indicating that one Pi plant was heterozygous for these characters. — Five F* 

 families were grown: A-l, A-2, B-l, B-2, C-l. Progeny in each showed 2 classes for flower 

 color, viz., dark violet or red-violet and pale-colored, the ratio in each family and in the 

 summation of families, closely approximating the 3: 1 ratio. Possibility of genotypic differ- 

 ences within each class noted. Among the pale-colored plants of families B-l and B-2 was 

 found a difference in color of the nerves <>n the outside of the corolla. They were either dark 

 violet or green (3 were greenish and pale violet below) in the ratio 3:1. As for anther color, 

 the progeny of Fi plants with yellow anthers were yellow while the progeny of blue-anthered 



