No. 1, February, 1921] GENETICS 31 



204. Harris, J. Arthur. Practical universality of field heterogeneity as a factor influenc- 

 ing plot yields. Jour. Agric. Res. 19:279-314. 10 fig. July 1, 1920.— Analysis is made of 

 actual yields of plot tests reported by investigators for various root, hay, grain, and fruit 

 crops. All fields were found to be heterogeneous, though they had been carefully selected 

 for yield tests because of apparent uniformity. Soil heterogeneity is shown to have a real 

 physical and chemical basis. — Author concludes that it is practically impossible to secure 

 fields suitable for a direct comparison of yields. This fact emphasizes need of greater care in 

 agronomic technique and of more extensive use of statistical method in analysis of the data 

 from plot trials. — See also Bot. Absts. 6, Entry 480. — C. M. Woodworth. 



205. Hartley, C. P. Better seed corn. U. S. Dept. Agric. Farmers' Bull. 1175. 14 P-, 

 9 fi^. 1920. — It is stated that low yields due to poor seed can be prevented by selecting seed 

 corn (maize) in the field in the fall, and instructions are given for gathering, storing, grading, 

 and testing the selected ears. Four experiments are summarized briefly as follows: (1) Varie- 

 ties that produce most in some states are among the poorest in others. (2) Seed ears from 

 the highest yielding rows of ear-to-row breeding plats have repeatedly produced better than 

 ears taken from poorer rows. (3) Well-preserved seed was found to produce higher yields 

 than seed injured by exposure, although both kinds germinated equally well. The difference 

 between the two kinds is accentuated when they are grown in fertile soil. (4) Diseased ears 

 or apparently healthy ears from diseased stalks give lower yields than disease-free ears from 

 normal stalks. — /. H. Kempton. 



206. Heal, John. Hippeastrum (Amaryllis). Gard. Chron. 68:60. July 31, 1920.— 

 Recounts the unsatisfactory results of crossing Hippeastrum pardinum with other Hip- 

 peastrums. Credits H. Leopoldii with more influence than any other Hippeastrum in pro- 

 duction of best forms. — J. Marion Shull. 



207. Heilbrunx, L. V. Studies in artificial parthenogenesis. III. Cortical change and 

 the initiation of maturation in the egg of Cumingia. Biol. Bull. 38: 317-339. May, 1920. — 

 When the egg of Cumingia is shed into sea-water, the first maturation spindle has formed, 

 but no polar bodies are thrown off unless the egg is fertilized or treated with the proper 

 reagents. The immature unfertilized egg is surrounded by a stiff vitelline membrane which 

 tightly encloses the fluid cytoplasm and effectively prevents the throwing off of polar bodies; 

 it is only when the egg is released from this restraint that maturation can proceed. Such a 

 release from restraint can be accomplished in three ways: by membrane elevation, by mem- 

 brane swelling, and by rupture of the membrane. Substances which themselves have low 

 surface tension produce a lowered surface tension of the membrane, and this results in its 

 elevation from the egg surface. Acids, alkalis, and certain salt solutions cause the vitelline 

 membrane to swell. The membrane may be removed from the egg by shaking, or it may be 

 caused to rupture by immersion in dilute sea-water. Maturation in Cumingia is not depend- 

 ent upon an increase in oxidation. Cortical change in Cumingia produces no increase in 

 permeabilit}'^ either to dissolved substances or to water. — Bertram G. Smith. 



208. Heinricher, E. £in Versuch Samen, allenfalls Pfltanzen, aus der Kreuzung einer 

 Laubholzmistel mit der Tannenmistel zu gewinnen. [An attempt to secure seeds, perhaps 

 plants, from the cross between the mistletoe of deciduous trees with that of the Coniferae.] 

 Ber. Deutsch. Bot. Gesell. 37:392-398. Dec, 1919. 



209. Henning, Hans. Mnemelehre oder Tierpsychologie? [The mneme theory or ani- 

 mal psychology?] Biol. Zentralbl. 39: 187-192. April, 1919.— Controversial article in which 

 rather incidentally author denies identity of "individual memory" and heredity.— A. 

 Franklin Shull. 



210. Hooper, J. J. Inheritance of Jersey colors. Jour. Dairy Sci. 2:290-292. 1919.— 

 This paper deals with the inheritance of self vs. broken color (white spotting), tongue color 

 and switch color, in Jersey cattle. The data are largely taken from the American Jersey 

 herd books. Broken color mated to broken color was found to give 194 broken color to 15 self 



