ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
393 
But this is not the sole cause of the difference. Whether the oxygen 
nets directly or indirectly on the movements is still uncertain. 
Caloritropic Phenomena of Roots.* * * § — Herr J. af Klercker describes 
an apparatus for measuring the curvatures caused in growing parts of 
plants by unequal temperatures, and the results of observations made 
chiefly on Pisum sativum, Faba vulgaris, Helianthus annuus, and Sinapis alba. 
For the movements manifested in an organ under the influence of the 
conduction of a stream of heat on one side only of the organ, he proposes 
the term caloritropic, as preferable to thermotropic. At all events with 
the first three species named, he finds, as a uniform result, that the 
caloritropic phenomena increase in intensity with an increase of tempe- 
rature. 
Positively Geotropic Flower.+ — Herr J. Wiesner describes what 
he regards as the first recorded instance of positive geotropism in a 
flower, in the case of Clivia nobilis (Agave®). The flower appears 
regular in the bud, but is monosymmetrical when fully developed. The 
movements of the flower dependent on growth are very complicated, the 
principal part being played by a form of nutation which is not dis- 
tinguishable from positive geotropism. The flower, which is at first 
straight, filtimately curves, owing to the co-operation of this force with 
epinasty. 
(4) Chemical Changes (including Respiration and Fermentation). 
Transformation of Chlorophyll-grains into Amyliferous Leucites.J 
— Prof. R. Chodat has followed out, in the pseudo-bulbs of Calanthe 
Sieboldii (Orchid eas) step by step, the transformation of grains of 
chlorophyll into leucites which produce starch. The colouring matter 
of the chlorophyll-grains becomes gradually limited to certain portions, 
and the grains of starch make their appearance first in the uncoloured 
portion. 
y. General. 
Effects of Earthquakes on Vegetation.§ — Sig. A. Goiran states 
that the effects of earthquakes on vegetation are to induce a more 
rapid germination of seeds, and a more rapid growth of the young 
plants, resulting in a greatly increased luxuriance of vegetation in the 
pastures, arable lands, vineyards, and shrubberies ; and this is accom- 
panied by an unusually deep green colour of the leaves. These results 
he believes to be due, not to the direct influence of the tremor, but to 
three secondary causes, viz. ; — (1) The increased production of carbon 
dioxide ; (2) the diffusion of nutrient fluids through the soil, acting as 
a kind of natural manuring ; (3) the production of electricity, which 
has been shown by Aloi [| to be favourable to the luxuriance of vegeta- 
tion. In other instances earthquakes have appeared to have an unfavour- 
able influence on vegetation ; but this is probably due to their having 
been associated with a long period of drought. 
* Ofvers. k. Vetensk.-Akad. Forliandl. Stockholm, 1891, pp. 765-90 (8 figs.). 
t Ber. Deutscli. Bot. Gesell., x. (1892) pp. 12-7. 
+ Ann. Sci. Nat. et Phys., xxiii. (1890) pp. 559-62 (1 pi.). 
§ Bull Soe. But. Ital., i. (1892) pp. 102-6. || Cf. this Journal, ante, p. 69. 
