ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
235 
special organisms. The first series of experiments included Pisum 
sativum, Bobinia Pseudacacia, Cytisus Laburnum, and Gleditsch la triacanthos. 
The results obtained confirmed those of Hellriegel that the nodule bac- 
teria give an impetus to vegetation, and hinder the formation of flower 
and fruit. All the successfully infected plants had nodules which 
varied in size and number in the different plants experimented 
upon. Thus in liobinia the nodules were generally larger but less 
numerous than on pea-roots. The quantitative results, amount of dry 
produce, and the amount of nitrogen in produce and in seed sown, are 
carefully given in several tables which accompany the paper. 
(3) Irritability. 
Nutation of the Sunflower.* * * § — Mr. W. A. Kellerman has observed 
the phenomena of nutation in a very large number of sunflowers; and 
finds it displayed more or less in 66 percent, of the specimens observed , 
34 per cent, not exhibiting any movement. In those which displayed 
nutation, the direction of the movement was very various, as also its 
intensity, very few approaching a semicircle. 
(4) Chemical Changes (including Respiration and Fermentation). 
Limits to the Accumulation of Carbohydrates in the Leaf.f — From 
a series of experiments on the leaves of Vitis vinifera and Labrusca, and 
Bubus fruticosus and csesius — leaves which remain fresh in direct sun- 
shine, if the stalks are placed in water, for as long as ten days after they 
have been gathered — Herr W. Saposclinikoff ascertained that sugar may 
accumulate in the cell-sap to as high a concentration as 6 - 8 per cent., 
while, on the other hand, the conversion of sugar into starch commences 
at a concentration of 2 per cent. It would appear therefore that two 
opposite processes are going on in the leaf at the same time, the forma- 
tion of starch out of sugar, and the conversion of starch into sugar. 
The weaker the concentration of the sugar, the more quickly is the 
starch dissolved, and vice versa. There is a degree of concentration- 
near the maximum amount of sugar in the leaf — at which there is an 
equilibrium between the two processes ; and in this condition no further 
increase of the sugar takes place. 
Influence of Phosphoric Acid on the Formation of Chlorophyll.}:— 
By a series of experiments on Algae, chiefly Spirogyra, Dr. O. Loew claims 
to have established that not only iron salts, but also phosphates, are 
essential to the formation of normal chlorophyll. 
Ripening of Cherries, Fermentation of Cherry and Currant Juice, 
and Colouring-matters of Red and Black Currants.§ — Herr W. Keirn 
deals in the first part of this paper with the change in chemical compo- 
sition which takes place during the growth and ripening of the fruit of 
Prunus Cerasus. The results are tabulated, and show a progressive 
increase in the percentage of acids and invert sugar. Succinic acid 
* Trans. Kansas Acad. Sci., xii. (1890) pp. 140-58. See Bot. Centralbl., 1891, 
Beih., p. 415. t Ber. Deutsch. Bot. Gesell., ix. (1891) pp. 293-300. 
t SB. Bot. Ver. Mlinchen, Dec. 14, 1891. See Bot Centialld., xlviii. (1891) p. 371. 
§ Zeitschr. Anal. Chem., xxx. pp. 401-7. See Journ. Chem. Soc., 1891, 
Abstracts, p. 1539. 
