630 EXPEEIMENT STATION EECORD. 



in the capacity to form certain substances and shiowing less dependence upon 

 external conditions). 



At the limits of genera physiological characters are modified in a quantitative 

 way, but slowly, probably not at all qualitatively. Species, as complex morpho- 

 logical and physiological characters, are established through a slow process of 

 evolution. Variation and evolution of physiological characters are easier to 

 understand from the Darwinian standpoint than from that of De Vries, accord- 

 ing to the author. 



It is held that a natural rather than a fortuitous systematic arrangement of 

 vegetable oils should be recognized. 



On the nature of mutations, R. R. Gates (Jour. Heredity, 6 {1915), No. S, 

 pp. 99-108, figs. 7). — Noting views which have been advocated regarding the 

 origin and fundamental nature of mutations, the author discusses some char- 

 acters of (EnotJiera lata, CE. gigas, and CE. rutricalyx in connection with their 

 behavior in regard to inheritance of chromosome numbers and other characters. 



It is claimed that any theory which will explain the origin of the (E. 

 ruhricalyx character, which is claimed to be inherited in simple Mendelian 

 fashion (unlike those of (E. lata or (E. gigas), will explain also the origin of 

 all Mendelian differences It is held that, as a rule, simple Mendelian char- 

 acters arise through alteration on the part of a chromosome analogous to the 

 mutations known to occur in certain bacteria. This type of change is considered 

 as sufficient to account for the origin of all mutations inherited in Mendelian 

 fashion. The change is considered to be fundamentally chemical rather than 

 morphological in its nature. 



The author concludes in general that mutations, which are of many kinds 

 and tend in many directions, furnish the material for real evolution. The 

 manner of inheritance of a character is determined, or at any rate limited, by 

 the manner of its origin, that is, by the nature of the germinal change by which 

 it occurred. Just as there are different types of discontinuity in variation, so 

 there are various methods of inheritance of the differences which thus arise, 

 these methods depending on the basic nature of the original change. 



Induced variations in chromogenesis, M. R. Smirnow {Ahs. in Science, n. 

 ser., 41 {1915), No. 1060, pp. 621, 622).— The author states that chromogenesis 

 may be increased not only by growing the bacteria on more favorable media 

 and environment, but also by the process of selection, transplanting each time 

 from the portion of the culture or from a colony that shows the most pro- 

 nounced pigmentation. 



Chromogenesis is considered to be more or less closely associated with the 

 metabolic activities of bacteria. It varies with the strain and is more or less 

 dependent upon oxygen, temperature, and the medium used. An organism may 

 produce more than one color at one and the same time, or it may produce 

 different colors, depending upon the environment and the medium used, particu- 

 larly the latter. 



Influence of the concentration of the nutrient substrate upon micro- 

 organisms, Zae Northeup {Abs. in Science, n. ser., 4I {1915), No. 1060, pp. 620, 

 621). — The effect of liquefying and nonliquefying organisms on gelatin media 

 containing different concentrations of gelatin was investigated. The size of the 

 colonies was found to be inversely proportional to the concentration of the 

 gelatin. This was especially marked in the case of the organisms which are 

 most active in liquefying gelatin. 



Halophytic and lime-precipitating bacteria, K. F. Kkllerman and N. R. 

 Smith {Abs. in Science, n. ser., 41 {1915), No. 1060, p. 624). — The authors report 

 that of approximately 70 cultures isolated from water from the Great Salt 

 Lake and sea water from Florida and the Bahamas three types of organisms 



