No. 1, May, 1921] GENETICS 41 



ing side should not become too extensive, that follow-up improvements be accompanied by 

 reward of original breeder, that selections can often be reasonably limited and that a gen- 

 eral testing of strains by public institutions is needed. [From anonymous review in Zeitschr. 

 Pflanzenziicht. 6: 189. Dec, 1918.]— James P. Kelly. 



270. Harlax, Harry V., and H. K. Hates. Occurrence of the fixed intermediate, Hor- 

 deum intermediiun Haxtoni, in crosses between H. vulgare pallidum andH. distichon palmella. 

 Jour. Agric. Res. 19: 575-591. 4 pl- 1920. — A barley, Hordeum intermedium Haxtoni, inter- 

 mediate between typical 6-rowed and typical 2-rowed, has been known for many years and 

 reported in literature as breeding true. Observations made since 1900 throw doubt on validity 

 of fixed intermediates which bear lateral, fertile, unawned florets. — Authors crossed Man- 

 churia and Svanhals varieties. Manchuria is typical 6-rowed and Svanhals has long-awned, 

 central, fertile florets, and awnless, sterile, lateral ones. F2 plants (87) produced F3 families 

 which were classified into 7 groups: (1) 22 plants, typical (phenotypical) 6-rowed; (2) 7 plants, 

 lateral florets short-awned, highly fertile; (3) 25 plants, lateral florets awns short to pointed, 

 fertility low; (4) 10 plants, lateral florets awns short to pointed, fertility nil; (5) 7 plants, 

 lateral florets large, awnless, fertility low; (6) 11 plants, lateral florets awnless, fertility nil; 

 (7) 5 plants, lateral florets small, awnless, fertility nil. Assuming a 2-factor hypothesis 

 the following genetic analysis developed with the expected number of plants as indicated: 

 (1) 22 plants homozygous for 6-rowed, A A BB, heterozygous for 6-rowed X regressive 6-rowed, 

 AABb, and homozygous for regressive 6-rowed, AAbb; (2) 11 plants heterozygous for 

 6-rowed X intermedium, AaBB; (3) 22 plants heterozygous for 6-rowed X 2-rowed, AaBh; 

 (4) 11 plants heterozygous for regressive 6-rowed X 2-rowed, Aahh; (5) 5 plants homozygous 

 for intermedium, aaBB; (6) 11 plants heterozygous for intermedium X 2-rowed, aaBb; (7) 5 

 homozygous for 2-rowed, aabb. The 2 groups of 7 sub-groups correspond very well. The 

 first sub-group in above groups is genetically complex. Factor AA is considered epistatic 

 to BB and so all plants of group 1 are phenotypically identical. Evidence of presence of a 

 third factor governing fertility is presented. Stability of intermedium form has been fully 

 confirmed. — L. R. Waldron. 



271. Herwerden, M. A. van. [Dutch rev. of: Broman, Ivar. Das sogenannte bioge- 

 netische Grundgesetz und die moderne Erblichkeitslehre. (The so-called biogenetic law and 

 modern genetics.) Bergmann: Miinchen and Wiesbaden, 1920.] Genetica 2: 529-530. 1920. 



272. Herwerden, M. A. van. [Dutch rev. of: Morgan, Thomas Hunt. The physical 

 basis of heredity. 14X21 cm., 300 p., 117 fig. J. B. Lippincott Co.: Philadelphia, 1919. 

 (See Bot. Absts. 5, Entry 422.)] Genetica 2: 542-544. 1920. 



273. Hogben, Lancelot. The problem of synapsis. Jour. Roy. Microsc. Soc. 1920: 269- 

 276. Sept., 1920. — Abrief critical review of recent work on the chromosomes. The important 

 point is made that there is not yet agreement concerning the origin of the chromosomes 

 pairing in synapsis nor in the method of pairing. The author thinks that, in view of the 

 uncertainty, emphasized by Miss Digby's recent papers, concerning the question whether the 

 chromosomes that pair in the heterotypic prophase are homologous paternal and maternal 

 chromosomes respectively or whether they represent only the daughter halves of a single 

 somatic chromosome which splits in the telophase of the last sporogenous cell (Digby), 

 "Such an attempt to provide an interpretation of partial linkage in Mendelian inheritance 

 is exceedingly ambitious" on the basis of the chiasmatype theory of crossing over. The gist 

 of the paper is contained in the conclusion that "While the chromosome hypothesis has proved 

 a great incentive to research — particularly in the problem of sex — its major premise, the 

 reality of synapsis, is in no way firmly established; further knowledge of the relation of 

 chromosomes to the organization of the resting nucleus and a specialized study of individual 

 heterotype chromosomes constitute, therefore, two of the most imperative needs of cytologi- 

 cal theory today." — Leonas L. Burlingame. 



