June 4, 1915] 



SCIENCE 



837 



is reached. Any considerable rise of temperature, 

 as in tempering, permits further spontaneous re- 

 lief of strain, or molecular rearrangement, doubtless 

 accompanied by more generation of heat, and so 

 on until annealing temperature is reached. It is 

 obvious that the process of tempering or annealing 

 steel is an exothermic one, and conversely that 

 hardening is an endothermic process. 



Diagrams of the apparatus employed are shown 

 and described, and analyses of the steels given. 



Buling and Performance of a Ten-inch Diffraction 

 Grating: A. A. Michelson. 



One-Dimensional Gases and the Reflection of Mole- 

 cules from Solid Walls: Eobeet Williams Wood. 



Heredity in Protozoa: M. H. Jacobs. 



In the higher animals, characters are not for the 

 most part directly transmitted from one genera- 

 tion to the next, but develop anew in each genera- 

 tion from the germ-plasm. In the protozoa, on the 

 other hand, there is a mixture of direct transmis- 

 sion and new development that has interesting 

 consequences in the case of the inheritance of 

 newly acquired characters. In this connection a 

 race of Faramecinm with three contractile vacuoles 

 instead of the usual number of two is discussed, 

 and the means described by which the unusual 

 number is kept from disappearing. The factors 

 concerned seem to be: (a) direct transmission of 

 the extra vacuole, (6) a tendency to adhere to an- 

 cestral racial traits, and (c) a new tendency of 

 the protoplasm to produce extra vacuoles. 

 The Constitution of the Hereditary Material: T. 



H. Morgan. 



The Problem of Adaptation as Illustrated hy the 

 Fur Seals of the Pribilof Islands: Geoege H. 

 Parker. 



The Alaskan fur-seal is a pelagic animal that 

 breeds in summer on the Pribilof Islands, Behring 

 Sea. About equal numbers of males and females 

 are born. At the breeding age one male, the bull, 

 becomes associated with a number of females, the 

 cows, thus constituting a harem. A harem may 

 contain as many as 120 cows and probably aver- 

 ages about 30. As a result of this disproportionate 

 relationship as compared with the proportion of 

 the sexes at birth, there are to be found at most 

 breeding-grounds many so-called idle bulls. These 

 are a measure of the inefficiency of organic adap- 

 tation. Contrary to the opinion held by many 

 biologists, adaptation is not always a relation of 

 great exactitude, but is often, to use the words of 

 Bateson, a poor fit. 



An Interpretation of Sterility in Hybrids: Edward 

 M. East. 



Heterosis and the Effects of Inbreeding : George 



H. Shull. 



Physiological processes are stimulated and rate 

 of growth and total amount of growth increased 

 through the union of gametes having unlike con- 

 stitution. This physiological effect of the differ- 

 ences in uniting gametes is heterosis. Inbreeding 

 lessens heterosis by gradually lessening the difEer- 

 ences between the uniting gametes. The applica- 

 tion of this principle to some of the problems of 

 practical breeding was briefly discussed. 



The Significance of Sterility in (Enothera: Bead- 

 let M. Davis. 



Studies on the seed, ovule and pollen sterUity in 

 (Enothera show that there are species wdth a high 

 degree of fertility and species in which fertility is 

 low, also that hybrids may exhibit a wide range in 

 comparative fertility. These conditions suggest 

 the possibility that hybrids may at times continue 

 indefinitely as impure or heterozygous species 

 through a failure to produce homozygous zygotes 

 or through the mortality of zygotes having homozy- 

 gous constitutions. (Enothera Lamarclciana is a 

 form with low seed fertility and a high degree of 

 pollen and ovule sterility, and may be representa- 

 tive of an impure species, hybrid in character, 

 which for the most part breeds true, but occasion- 

 ally and repeatedly produces other types, the so- 

 called mutants. In genetical work with CEnotheras 

 a method of germinating seeds must be employed 

 which will give trustworthy proof that a culture 

 has produced all of the seedlings possible from a 

 sowing of seed-like structures. 



Morphology and Development of Agaricus rod- 



mani: George F. Atkinson. 



Agaricus rodmani, which is closely related to the 

 cultivated mushroom, Agaricus campestris, has a 

 thick, double annulus, which is divided into an 

 upper and lower limb by a broad, marginal groove 

 nearly reaching the stem. This peculiar annulus, 

 especially the lower limb, has suggested a resem- 

 blance to the volva of the Amanitas. While it 

 arises from the surface of the pileus margin, and 

 is composed to some extent of a portion of the 

 blematogen, it is not strictly comparable to the 

 volva, since the blematogen in the species of 

 Amanita thus far studied is clearly separated 

 from the pileus by a distinct cleavage layer, while 

 in Agaricus it remains "concrete" with the 

 pileus. 



