ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 317 



succulent plants, mycorhizal forms, geophilous and aerial shoots, meso- 

 phytes and spiny xerophytes ; and the plants were grown from tubers, 

 conns, rhizomes, cuttings of leaves and stems, seeds, and spores. 



The author gives a useful historical account which includes notices 

 of nearly all of the more important researches bearing upon the subject, 

 from Ray and Hales onward to the beginning of the present century. 

 Then follows a detailed account of his own experiments on nearly one 

 hundred different species. The arrangement is an alphabetical one, 

 under the name of the plant which formed the subject of experiment. 



The chapter on " General Considerations " supplies a useful corre- 

 lation of the results of these experiments, and includes also critical 

 remarks on work of other observers. The remaining pages of the memoir 

 are occupied with several short chapters. " Theories as to the nature of 

 etiolation," is a brief resume of explanations advanced by previous 

 workers. In " Morphogenic influence of light and darkness," the author 

 points out that examination of the facts obtained by absolute etiolations 

 shows that no one of the theories recorded in the preceding section is 

 capable of general application to the behaviour of all plants in darkness. 

 " The phenomena of etiolation rest upon, and consist in the behaviour of 

 the plant consequent upon the absence of the morphogenetic influence 

 of light. Some species show an adaptation to this absence of light, or 

 to the positive influence of darkness, by which the shoots or petioles are 

 elongated in such manner as to constitute an effort to escape from 

 darkness, or to attain illumination." There are also chapters on the 

 " Influence of etiolation upon chemical composition," and " The rate 

 and mode of growth as affected by light and darkness." 



J Chemical Changes. 



Decomposition and Regeneration of Albuminoids in Plants.* — 

 Oabrielle Balicka-Iwanowska finds as a result of a series of experiments 

 with the yellow lupin that the asparagine which is formed during decom- 

 position of albuminoid bodies is a secondary product, acid amides and 

 hexonic bases being the primary products. Also that mineral salts 

 exercise a certain influence on the regeneration of albumin at the ex- 

 pense of the products of its decomposition. Defect of calcium is the 

 most important cause of diminution in the product of albumin. As 

 regards the effect of light on accumulation of asparagine, and its subse- 

 quent use for the regeneration of proteids, the author finds that while 

 photosynthesis has an effect on the regeneration of proteids, light itself 

 seems to exercise a direct effect. 



Function of Peroxides in the Living Cell.t — R. Chodat and 

 A. Bach have studied the toxic action of hydrogen peroxide. Different 

 species of fungi were grown in a nutritive solution, to which variable 

 amounts of hydrogen peroxide were added. The results show that this 

 peroxide is not very toxic, since some species (e.g. Sterigmatocystis nigra) 

 will fructify in a 2 p.c. solution. Peroxides occur in plants ; they are 

 the so-called oxydases of Bertrand and others. The authors, by passing 



• Bull. Int. Acad. Sci. Cracow, CI. Sci. Math, et Nat., 1903, pp. 9-32. 

 t Biblioth. Univers. Arch. Sci. Thys. et Nat., se'r. 4, xiv. (1902) pp. 510-2. 



June 17th, 1903 y 



