ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 411 



united with bases, forming either neutral or acid salts. By far the 

 most widely distributed of the organic acids is malic ; the bases are 

 either organic or inorganic ; the latter chiefly potassa and lime ; the 

 former comprise various nitrogenous compounds. The proportion 

 of acids present varies greatly ; it is dependent on external circum- 

 stances, but is usually greatest in the young growing parts, dimi- 

 nishing gradually with the age of the organ, In young organs they are 

 most commonly present in the form of salts of potash, which is, at a 

 later period, replaced by lime. In addition to their function in pro- 

 ducing turgidity, these acids also play an important part in being the 

 agents by means of which potash is absorbed through the root. 



Metastasis and Transformation of Energy in Plants.* — A. 

 Famintzin publishes an elaborate handbook on this subject, founded 

 on the researches of Pfeffer, Detmer, and others. He classifies the 

 subject under four heads, as follows : — (1) Chemical composition of 

 plants ; (2) Organic sources of nutriment ; (3) Synthesis of organic 

 compounds ; and (4) The interchange of material between plants and 

 their environment. 



Under the first head the author includes not only the organic 

 but also the inorganic constituents of plants ; as also the crystal- 

 line deposits and cystoliths. The second treats of germination and 

 nutrition, including that of insectivorous plants ; and of parasites, 

 whether containing chlorophyll or not. The theory of fermentation 

 and structure of ferments is also included here ; and the phenomena 

 connected with fermentation are again discussed more in detail in the 

 third part. The fourth section treats of the properties of naked 

 protoplasm, the interchange of substance in a cell inclosed in a cell- 

 wall (diosmose), the absorptive powers of roots and leaves, the move- 

 ments of gases and water, and the transport of protoplasmic sub- 

 stances. The author does not agree with Sachs's view that metastasis 

 is always accompanied by a loss of weight. 



Action of the different Rays of Light on the Elimination of 

 Oxygen. f— J. Reinke has designed an apparatus for determining this 

 much-disputed question, which he calls a spectrojphore. 



A horizontal bundle of rays passes from the heliostat through a 

 vertical slit into the dark chamber, and then through a telescope 

 objective at a convenient distance to a sufficiently large prism, placed 

 at the least possible deviation from an angle of 60°, producing a sharp 

 objective spectrum on a screen. The screen consists of two vertical 

 level boards, which can be so moved in a slot that their edges can 

 either be brought close together or placed at any distance from one 

 another ; any required portion of the spectrum being then allowed to 

 pass through the opening. Immediately behind the screen is a large 

 convex lens on which the rays fall, and are collected into a focus in a 

 small image of from 1 to 2 sq. cm. By this means any required area 

 of the spectrum can be cut ofi". When the screen is entirely opened, 



* Famintzin, A., ' Metastasis and Transformation of Energy in Plants,' 

 (Kiissian\ 816 pp., St. Petersburg, 1883. See Bot. Centralbl., xvii. (1884) p. 97. 

 t Bot. Ztg., xlii. (1884) pp. 1-10, 17-29, 33-46, 40-59 (1 pi.). 



