164 GENETICS [Bot. Absts., Vol. VI, 



described. Author records contribution of a fund by a Surinam breeding association by which 

 a selection inspector for the plantations is supported. Figures are given on varying produc- 

 tivity of coffee and cocoa trees with number of individuals selected as mother plants. Methods 

 of vegetative propagation are described. [From anonymous review in Zeitschr. Pflanzen- 

 ziicht. 7: 138-139. Dec, 1919.]— J. P. Kelly. 



1132. Tammes, T. De leer der erffactoren en hare toepassing op den mensch. Rede, 

 uitgesproken bij het aanvaarden van het ambt van buitengewoon hoogleeraaraandeRijks-univer- 

 siteit te Groningen. [The theory of hereditary factors and its applicability to man. Address 

 delivered on assumption of the office of Professor Extraordinarius in the State University at 

 Groningen.] 24 P- Wolters: Groningen, 1919. — A discussion of the principles of factorial 

 constitution of organisms; the writer thinks them as Morgan does, localized in the chromo- 

 somes, according to the linkage of all Drosophila-iactors in four groups and of all Pisum- 

 factors in seven groups, in harmony with their haploid chromosome numbers 4 and 7. If 

 then these principles might be applied to improvement of the human race, the great number of 

 chromosomes in man (diploid 47 and 48) is a difficult hindrance for locating the various hu- 

 man hereditary factors in the chromosomes; the inheritance of human characters is very com- 

 plicated and it is therefore impossible to give certain indications for human amelioration. 

 But possible is the amelioration of circumstances of life for man ; it changes only the phenotype 

 not the genotype, but it is the only thing we can obtain in the nearest future. — M. J. Sirks. 



1133. Thomson, J. Arthur. [French rev. of: Larger, R. Theorie de la contre-evolu- 

 tion, ou degenerescence par l'heredite. [Theory of retrogressive evolution, or degeneration by 

 heredity.] xiv + 405 p., 21 fig. Felix Alcan: Paris, 1919.] Scientia 14: 52-54. 1920. 



1134. Thomson, J. Arthur. [French rev. of: Hegner, R. W. The germ-cell cycle in 

 animals, x + 346 p., 84 fig. Macmillan & Co. : New York, 1914.] Scientia 14: 51-52. 1920. 



1135. Tjebbes, K., and H. N. Kooiman. Erfelijkheidsonderzoekingen by boonen. III. 

 Albinisme. [Hybridization experiments with beans. III. Albinism.] Genetica 1: 532-538. 

 1 pi., 3 fig. Nov., 1919. — The authors have made some experiments with a strain of albino- 

 throwing beans of the species Phaseolus vulgaris. The seeds of one plant, E. 9. 1916, sown 

 in 1917, gave 26 green-leaved plants and 8 ivory-white ones, indicating monohybrid segrega- 

 tion. 1918 the rest of the seeds from E9. 1916, produced again about three green seedlings: 

 1 white one. — 1918 albinotic seedlings were grafted on normal green ones. The best method 

 proved to be splice-grafting, the hypocotylof the albinotic seedling and a node of the green one 

 being cut across diagonally and united by means of a string of wet raffia. The albino then 

 can profit from the food present in the cotyledons and of the green leaf, left to the node. — 

 In this way two plants in 1918 and two descendants of one of these in 1919 were raised to 

 maturity and all of them produced the first, simple, leaves without the least trace of green 

 color, developing little patches of chlorophyll on the compound leaves and green stripes on 

 the pods. — As to the origin of this strain the authors venture to suggest, that it may have 

 arisen from the cross of a flower on an albinotic branch with a flower on a normal one, of a 

 sectorially chimaeric plant. Also the loss of the factor, that enables the plant to make 

 chlorophyll, may have taken place in one flower. The question too arises, whether the green 

 patches on the leaves and the stripes on the pods are caused by some chemical influence of 

 the normal plant or that we deal with an extreme case of variegation. To clear this and other 

 questions the work will be continued. — H. N. Kooiman. 



1136. Urban, J. Hochpolarisierende Rube und ihre Nachkommenschaft. [High-polar- 

 izing beets and their progeny.] Zeitschr. Zucker-Industr. Bohmen 42: 387-391. 1919. — Three 

 groups of mother beets whose average sugar content were 20.28 per cent, 20.66 per cent and 

 21.14 per cent respectively gave progeny whose averages were 21.47 per cent, 21.29 per cent 

 and 21.59 per cent sugar. Three generations showed no noticeable influence of small differ- 

 ences in sugar percentage of mother beets upon averages of progeny. Same mother beets 

 seriated for weights showed a negative correlation between size and sugar percentage. [From 

 anonymous review in Zeitschr. Pflanzenzucht. 7: 141-142. Dec, 1919.] — J. P. Kelly. 



