March 29, 1883] 
NATURE 
593 
Mechanism of the Scattering of Seeds and Fruits, with 
Special Reference to Torsion.” The paper deals with 
the torsion in the awn of grasses, such as Avena sterilis 
and Stipa pennata, torsion of the legume of Orobus and 
Caragana, the curving and torsion of the awn or beak of 
the fruits of Geraniacez, and the scattering of the seeds 
of Oxalis, and is illustrated by three plates. The author 
points out the relation of the different phenomena ob- 
served to the mechanical cells in the part, as demonstrated 
by a microscopical exaniination of the different structures. 
Sometimes the cells of the part contract, at other times 
they swell up, and one or other or a combination of both 
these causes, gives rise to the effects noticed in the dif- 
ferent plants under examination. Thus swelling of the 
cell-walls causes the remarkable ejection of the seeds of 
Oxalis. Unequal contraction of the mechanical cells 
causes the movements in the beaks of Geraniacez, and 
combined contraction and swelling in different layers of 
cells may be observed in the awns of Stipe and 
Avena. 
In the second part under consideration, namely, vol. 
xiii. part 3, there is a paper by E. Godlewski, with the 
title “Contributions to the Knowledge of Vegetable 
Respiration.’ The details of a large number of experi- 
ments are given which were made, with an ingeniously 
contrived and simple apparatus, upon the respiration of 
germinating seeds with both fatty and starchy endosperm, 
and a smaller series of experiments made on the respira- 
tion of the flower buds of Papaver somniferum and on the 
ripening fruits with oily seeds of the same poppy and the 
castor oil plant. Some of the more important results as 
set forth by Godlewski himself may here be alluded to. 
During the early stage of germination in which the seeds 
swell up by imbibing water, the volume of CO, given off 
equals or is only a iittle Jess than the volume of oxygen 
taken up, both in fatty and in starchy seeds. When the 
swelling takes place under water or when air is excluded, 
intramolecular respiration takes place. When air is 
admitted the intramolecular respiration does not imme- 
diately cease, but is gradually replaced by normal respira- 
tion. As the rootlets of the seedlings are developed the 
volume of carbonic acid gas evolved gradually diminishes 
in proportion to the quantity of oxygen taken up, so that 
at the period of most active respiration only from 55-65 
volumes of CO, are given off for every 100 volumes of O 
taken up. The formation of transitory starch during the 
germination of fatty seeds probably depends upon the 
action of atmospheric oxygen in each molecule of fat, 
converting it into CO,, water, a certain quantity of an un- 
determined substance, and three molecules of starch. In 
the later stages of germination of fatty seeds the tran- 
sitory starch is used as well as the fat, so that the differ- 
ence between the volume of CO, given off and O taken 
up became gradually smaller, until at last the volumes 
are equal. d 
In the germination of starchy seeds the volume of CO, 
given off in all stages nearly equals that of O taken up, 
in peas sometimes a little more or a little less, but in 
wheat maintaining a seemingly constant relation of 1 to 
105, the CO, being a little in excess of the O taken up. 
In the buds of Papaver somniferum the CO, given off 
practically equals the O taken up (100°9 CO, for every 
100 vols. O). In ripening fruits with oily seeds more 
CO, is given off than O absorbed ; in Papaver somniferum 
150 CO, for every 100 vols. of oxygen. 
When oxygen is supplied under diminished pressure, 
respiration is variously influenced in different parts of the 
plant, but respiration is more affected in fatty than in 
starchy seeds. When the pressure of the oxygen is very 
slight 7ovma/ respiration is reduced to a minimum, and 
intramolecular respiration commences. Intramolecular 
respiration is, under normal conditions, not a primary 
phenomenon as Pfeffer and Wortmann assert. Vormal 
respiration consists in the immediate action of atmo- 
spheric oxygen upon the molecules of living protoplasm. 
Intramolecular respiration only begins when the normal 
respiration is rendered difficult by the want of atmospheric 
oxygen. Under ordinary conditions intramolecular re- . 
spiration only begins when processes of reduction are 
going on in the plant as when fat is formed from carbo- 
hydrates. 
The concluding paper in this part is “ Contributions to 
the Anatomy and Mechanism of the Rolling up of the 
Leaves of certain Grasses,’ by Dr. A. Tschirch, with 
three plates. In this paper the author fully describes the 
mechanism by which such grasses as Wacrochloa tena- 
cissima (Esparto), Lygeum spartum, Aristida pungens, 
and others, which he groups as Steppe grasses, roll up 
their leaves in dry weather to protect the upper surface 
which bears the stomata, and prevent too great evapora- 
tion. 
The first paper in the part and the longest is by the 
editor, Dr. N. Pringsheim, himself, ‘‘On the Function of 
Chlorophyll and the Action of Light in the Plant.” This 
paper is a controversial one, issued in the form of an 
open letter to the Philosophical Faculty of the University 
of Wiirzburg. The first part of the paper includes a 
“personal defence,” in which the statements contained 
in a paper by Dr. A. Hansen, with the title “ History of 
Assimilation and the Function of Chlorophyll,’ pub- 
lished separately as a ‘‘ Habilitationsschrift,” and also re- 
printed in Sachs’ “‘ Arbeiten,’” vol. ii. p. 557, are minutely 
criticised. The second part of the paper is an historical 
discussion of the theory of assimilation, of the function 
of chlorophyll, and of the action of light on the plant. In 
this part Pringsheim does not seem to bring forward any 
new experiments, but gives a careful véswmé of the whole 
subject under three heads. These are (1) Problem of 
the primary action of light on the cell ; (2) the function 
of the colouring matter of chlorophyll in the exchange of 
gases in the plant ; and (3) the function of the chlorophyll 
bodies and the primary product of assimilation of carbon. 
Into the merits of the controversy we cannot enter. 
W. R. MCNAB 
___ = a a eee eee ee 
OUR BOOK SHELF 
Mexico To-day. By Thomas Unett Brocklehurst. 
(London: Murray, 1883.) 
DURING a recent tour round the world Mr. Brocklehurst 
turned from the beaten track in the United States south- 
wards to Mexico, where he spent seven profitable months 
in the capital and neighbourhood in the year 1881. 
Since the suspension of our diplomatic relations with that 
country in 1860, great difficulties have been felt in pro- 
curing accurate information regarding its internal rela- 
