40 GENETICS [Bot. Absts. 



in 1897 near the town of Norrkoping (Sweden) and is now in the botanical museum of Lund. 

 Petals are absent and stamens seem to be numerous. By close study it is seen that small 

 accessory flowers often consisting of only stamens have taken the place of all the four petals. 

 Especially in the lower parts of the inflorescences, are often found more or less petaloid parts 

 as traces of nectaries. Sometimes also a flower-stalk is developed. Sepals and gynoecium 

 have not been found in these accessory flowers. Author supposes that these flowers have 

 grown out from new points of vegetation in the axils of the petals and in close connection 

 with the same. Most organs of the accessory flowers are developed from these new growing- 

 points, but at least one of the outside ones is supposed to be grown out from the petal initial. 

 — K, V. Ossian Dahlgren. 



275. Murray, J. G. Relation of the supplying ovary to the causation of sex. Johns Hop- 

 kins Hosp. Bull. 29: 275-278. 1918.— See Bot, Absts. 3, Entry 654. 



276. Norton, J. B. S., and C. E. Leathers. Conditions detrimental to seed production. 

 Maryland Agric. Exp. Sta. Bull. 216: 175-226. 1918— See Bot. Absts. 1, Entries 628 and 747; 

 2, Entry 730; 3, Entry 656. 



277. Olson, P. J., C. P. Bull, and H. K. Hayes. Ear-type selection and yield in corn. 

 Minnesota Agric. Exp. Sta. Bull. 174. 60 p., 9 fig. 1918. — This is an investigation of the 

 relation of various characteristics of the seed ear to its yielding qualities. The study 

 includes such score-card points as length, weight, circumference, shelling percentage, perfec- 

 tion of butts and tips, kernel uniformity, variety, character, and maturity. Two methods of 

 experiment were employed: 1, analyzing the data obtained from ear-to-row breeding plots; 

 2, selecting diverse types of ears and comparing their yields. Work by former method 

 includes three different varieties of corn grown at four different locations and tests by latter 

 method ran through three successive seasons. A critical study of all the results fails to show 

 any significant relation between these ear characters and yield. — L. H. Smith. 



278. Plough, Harold H. Linear arrangement of genes and double crossing over. Proc. 

 Nation. Acad. Sci. [U. S. A.] 5: 167-168. May, 1919— See Bot. Absts. 3, Entry 659. 



279. Popenoe, Paul, and Roswell H. Johnson. Applied eugenics. 14 X 20 cm., v + 

 459 p., 46 fig. Macmillan Co.: New York, Oct., 1918. — General text-book on the subject of 

 eugenics, presenting a discussion of the principles and investigations in this field. Consider- 

 ably more attention is paid to the social forces controlling racial fortunes than to the method 

 of inheritance of specific traits. The relation between eugenics and specific social reforms is 

 discussed in considerable detail. Especially valuable are the chapters on the "Improvement 

 of sexual selection" and "Increasing the marriage rate of the superior."—//. H. Laughlin. 



280. Porter, William C. Huntington's chorea; a report of a family history study made in 

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

 1918.— See Bot. Absts. 3, Entry 2179. 



281. Preiser, Samuel A., and Charles B. Davenport. Multiple neurofibromatosis 

 (von Recklinghausen's disease) and its inheritance: with description of a case. Eugenics Rec. 

 Office Bull. 19. 34 p., 26 fig. Oct., 1918. — The classical symptoms of this disease are "sessile 

 or pedunculated swellings or tumors, sometimes soft and elastic, sometimes firm and tough, 

 that vary in size from that of a millet-seed to that of a child's head." They appear to 

 receive new stimuli at puberty and pregnancies. Associated with it are sometimes found 

 scoliosis, sexual impotency, or fecble-mindedness. — The disease is found only in about 1 in 

 2000 cases that present themselves to medical clinics or private practitioners for skin dis- 

 eases. It is highly hereditary, and behaves like a dominant trait. The specificity of loca- 

 tion, type and behavior in given families is very striking. — Twenty-nine pedigree charts are 

 printed with the text. There is a bibliography of 119 titles. — //. H. Laughlin. 



