ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
101 
conditions, nearly constant, and apparently independent of soil, climate, 
and other external conditions; but under exceptional conditions this 
proportion can be varied, and in a direction contrary to that which 
has usually been the case in other experiments. A transformation 
of male into female flowers takes place in conditions which are un- 
favourable to the development of the vegetative organs. 
( 2 ) Nutrition and Growth (including 1 Germination, and Movements 
of Fluids). 
Dependence of the Chlorophyll-Function on the Chromatophores 
and the Cytoplasm.* — According to Dr. L. Kny, the chlorophyll-pig- 
ment has no power of decomposing carbon dioxide when removed from 
the living plant, or when its organic matrix — the chromatophore — is 
killed. The elimination of oxygen in the light may, however, proceed 
when the cytoplasm has lost its motility and withdrawn from the cell- 
wall, or when the nucleus has become disorganised. Constant electric 
currents and induction currents appear to promote the assimilation of 
carbon dioxide in the light. 
Mixed Grafts.f — M. L. Daniel uses this term for grafts in which 
some of the buds of the stock are still allowed to remain, instead of all 
being destroyed. This brings about a certain degree of symbiosis be- 
tween the graft and the stock ; the former acquiring some of the pro- 
perties of the latter. The process is, therefore, to be used when it is 
desired to produce new varieties, rather than when it is the object to 
perpetuate existing forms. 
Absorption of Organic Matters by Boots.J — From experiments made 
on maize grown in a mineral solution containing glucose or invertin, 
M. J . Laurent states that the quantity of sugar absorbed is in proportion 
to the dry weight of the plant ; and that the saccharine matters thus 
absorbed are utilised by the plant, a large portion being oxidised into 
carbon dioxide. 
Influence of the Rontgen Rays on Yegetation.§— Professor G. F. 
Atkinson finds the effect on the higher plants of exposure to the Rontgen 
rays to vary according to the time of exposure. In periods varying from 
1—10 hours, no perceptible injury resulted ; while an exposure of 45 hours 
produced the same effect as total darkness. Species of Mucor, Oscillcitoria , 
and Bacteria were exposed to the action of the rays, but no influence was 
observed on their growth or movement. 
Assimilating Energy of Blue Light. ||— Herr F. G. Kohl gives fur- 
ther evidence in support of his view of the powerful effect of the blue 
rays of the. spectrum in promoting assimilation, which is merely an 
exemplification of Engelmann’s general law of the coincidence of the 
maxima and minima of absorption and of assimilation. The absorption 
of the blue rays is effected by the carotin of the chlorophyll, which has 
for its function the utilisation of these rays in assimilation. 
* Ber. Deutsch. Bot. Gesell., xv. (1897) pp. 388-403. 
t Comptes Rendus, cxxv. (1897) pp. 661-4. i Tom. cit., pp. 887-9. 
§ Rep. Brit. Ass., 1897 (Toronto). See Nature, lvi. (1897) p. 600. 
II Ber. Deutsch. Bot. Gesell., xv. (1897) pp. 361-6 (1 pi.). Cf. this Journal, 
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