ZOOLOGY AND BOTANY, MICROSCOPY, ETC, 
87 
(2) Nutrition and Growth (including- Germination, and Movements 
of Fluids). 
Elective Metabolism.* * * § — Prof. W. Pfeifer discusses the problem of 
the specific difference displayed by plants in the proportion absorbed of 
different nutrient substances. This is especially displayed in the absorp- 
tion of carbon compounds ; and can be studied with advantage in the case 
of fungi such as Aspergillus niger and Penicillium glaucum, When two 
substances of different nutritive properties are presented 'at the same 
time to the same plant, it will absorb the more nutritive one in preference 
to, and sometimes to the entire exclusion of, the less nutritive one ; 
though this is not always the case. Thus, when dextrose and glycerin 
are both presented to Aspergillus niger , and the former is greatly in 
excess, the latter will be entirely neglected ; while, if the proportion of 
dextrose is but small, some of the glycerin will also be taken up. 
Peptone may, in the same way, partially or entirely protect glycerin and 
dextrose lactic acid, from absorption by fungi. 
Effect of the Electric Light on Vegetation. — M. G. Bonnier f has 
carried out a series of observations, with the view of comparing the 
influence of the electric light, both continuous and interrupted, on plants, 
with that of normal daylight. The general result is that a continuous 
electric light promotes the formation of chlorophyll, and, at the same 
time a simpler anatomical structure of the leaves. Under a continuous 
electric light the distribution of chlorophyll in the tissues is more 
extended than in ordinary daylight ; chlorophyll-grains make their 
appearance in the cortex as far as the endoderm, and even in the 
medullary rays and the pith. The palisade-tissue of the leaf is reduced 
or disappears entirely, and the epidermal cell-walls are thinner. The 
hark is less developed, and the various tissues of the stem are less 
differentiated. When the electric light is discontinuous (12 hours in 
the 2-1) the effect on vegetation is intermediate between that of normal 
light and that of a continuous electric light. Alpine plants cultivated 
under a continuous electric light exhibit points of structure identical 
with those of Arctic plants. 
Effect of Electricity on Vegetation.^ — Prof. A. Aloi gives further 
evidence in favour of his previous statement that both terrestrial and 
atmospheric electricity exercise a favourable influence on the germina- 
tion of seeds and on the growth of plants. He predicts that the employ- 
ment of electricity will be a most useful element in the future of 
agriculture. 
Influence of Sudden Changes of Turgor and of Temperature on 
Growth.§ — Mr. R. H. True gives the following as the result of a series 
of experiments on this subject : — Following a sudden fall or a sudden 
rise of the temperature between 18 •0°-21 , 0° and O'S 0 -].^ 0 C. as 
extremes, the f rst effect seen is a slight turgor-change due to physical 
causes, producing, or tending to produce, a shortening in length if the 
* Ber. Verhandl. ’K. Sachs. Gesell. Leipzig, 1895, pp. 324-9; Jahrb. f. wiss. 
Bot. (Pfeffer u. Strasburger), xxviii. (1895) pp. 205-68. 
t Rev. Gen. de Bot. (Bonnier), vii. (1895) pp. 241-57, 289-306, 332-42, 409-19 
(10 pis.). X Bull. Soc. Bot. Ital., 1895, pp. 188-95. Cf. this Journal, 1892 p. 69. 
§ Ann. Bot., ix (1895) pp. 365-402. 
