60 GENETICS [Bot. Absts., Vol. V, 



of increased temperature upon the eggs before they are laid, because the flies raised at 20 c 

 did not tend to produce eggs any less resistant after they had been laying in the high tempera- 

 ture for a week or 10 days. Cultures of flies could not be held at 30° for successive generations ; 

 but if the adults of each generation were removed from high temperature for 24 hours or more 

 within a week after they hatched, the culture could be continued for the rest of the time at 

 this temperature. One culture was continued in 30° by means of this intermittent cooling 

 for ten generations and another culture was raised for 15 generations uninterruptedly at 28°; 

 in neither case did there appear any sign of adaptation. The flies were still unable to produce 

 more than one generation at a continuous temperature of 29° or over. "There is no evidence 

 of any hereditary adaptation to higher temperature." — E. C. MacDowell. 



434. Oberstein, O. Uber das Vorkommen echter Knospenvariationen bei pommerschen 

 und anderen Kartoffelsorten. [Occurrence of true bud variation in Pommeranian and other 

 varieties of potato.] Deutsch. Landw. Presse 1919: 560-561. 1 pi. 1919. — See Bot. Absts. 

 5, Entry 296. 



435. Ohly. Ziichterische Beobachtungen in einer Merinofleischschafherde. [Breeding 

 observations in a Merino sheep herd.] Mitteil. Deutsch. Landw. Ges. 1918: 235. 1918. 



336. Pascher, A. Oedogonium, ein geeignetes Objekt fur Kreuzungsversuche an ein- 

 kernigen haploiden Organismen. [Oedogonium, a suitable object for the study of crossing in 

 uninucleate haploid organisms.] Ber. Deutsch. Bot. Ges. 36: 168-172. 1918. — Importance of 

 study of results of crossing haploid organisms is emphasized, as illustrated by the work of 

 Burgeff with Phycomyces and of Pascher with Chlamydomonas . Author reports successful 

 crosses between two species of Chara and between two species of Spirogyra. After a discus- 

 sion of the advantages, disadvantages, and difficulties offered by various groups of algae for 

 work of this nature, it is reported that species of Oedogonium have shown themselves very 

 favorable for hybridization experiments. Most species of this genus are easily cultivated; 

 the isolation of single filaments and the bringing them together in desired combinations 

 within a confined space, such as a small tube, offer no difficulties; the filaments with maturing 

 oospores can be transferred to agar, where they readily complete their development; the zoo- 

 spores of different species are marked by characteristic differences in such respects as the shape 

 of the cell as a whole and the form of the anterior end; and the oospore, on germinating, gives 

 rise to four zoospores, whose nuclei result from the reduction divisions, and which resemble, 

 except in size, the zoospores produced by vegetative cells of the same species. In making a 

 cross, the female at least must belong to a dioecious species. Probably dioecious forms with 

 dwarf males are especially suitable. In cultures containing several species, the author has 

 found forms which, especially in the characters of the oospores, betrayed a hybrid nature. 

 It is probable that some forms which have been described as species were really hybrids. 

 A list of species of Oedogonium is given which are recommended for experiments in hybrid- 

 ization. — C. E. Allen. 



437. Pearl, Raymond. [Rev. of : East, Edward M., and Donald F. Jones. Inbreed- 

 ing and outbreeding: their genetic and sociological significance. 14x21 cm., 285 p., Jfi fig. 

 J. B. Lippincott: Philadelphia, 1919.] Science 51: 415-417. April 23, 1920.— See Bot. Absts. 

 4, Entry 571. 



438. [Pearson, Karl.] Quadrature coefficients. Biometrika 12: 000. Nov., 1919. — 

 Formulae from Biometrika I, p. 276, are reprinted as preface to a table by P. F. Everitt to 

 facilitate the calculation of areas within a curve. — John W. Gowen. 



439. Petren, A., and others. Angaende skrivelse till Konungen med begaran om 

 utredning och forslag i fraga om upprattandet av ett svenskt rasbiologiskt institut. — Motion n:o 

 7 i Forsta Kammaren. [Concerning a writing to the Swedish government proposing an extrica- 

 tion of and a project to establish a Swedish eugenical institute. Motion n :o 7. in the first Cham- 

 ber of the parliament. Bihang till riksdagens protokoll 1920. 190 x 225 mm., 27 p. Stock- 



