ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
545 
not, in the Graminefe, present that degree of differentiation in which the 
mineral matters are sharply separated off as a globoid from the proteid 
constituents of the grain ; only the membrane is here differentiated. 
The authoress advocates the view of there being one mother-substance 
in flour which readily undergoes hydration, giving rise to gluten. 
Mineral Food-materials of Plants. — A fresh series of experiments 
confirms Dr. H. Molisch* * * § in his previous view that iron is an essential 
constituent of the food of the lower fungi, and that it cannot be replaced 
by cobalt, nickel, or manganese. In opposition to the statement of 
Nageli, he finds that magnesium is also indispensable, and cannot be 
replaced by calcium, barium, strontium, zinc, or cadmium. Cadmium 
salts, even in very dilute solutions, are poisonous to fungi. The only 
element with which fungi can dispense, and which is essential to the 
higher plants, is calcium. 
Dr. W. Benecke f arrives generally at the same results as Molisch, 
especially with regard to Penicillium glaucum and Aspergillus niger. 
Magnesium is indispensable to their growth, and cannot be replaced by 
strontium. As a general result from these experiments, sulphur, phos- 
phorus, potassium, magnesium, and iron are indispensable to all plants, 
and calcium also to green plants. 
Quantity of Soluble Substances contained in Plants.^ — According 
to M. E. Gain the quantity of soluble substances contained in the water 
present in the tissues of plants increases with that of the water absorbed 
from the soil ; the different tissues presenting very important differences 
in this respect. The distribution of these substances varies according 
as the plant is growing in a moist or in a dry soil. The amount is 
larger in the parts near the summit of the plant than in the base of the 
stem or in the root. 
Fatigue-substances. § — Herr G. Jaeger claims priority over Reinitzer 
in the discovery of the fatigue-substances of plants, which are thrown 
off as excretory products, and which act prejudicially on the life of the 
plant. 
(33 Structure of Tissues. 
Process of Splitting in Anomalous Climbing Stems. || — Herr H, 
Schenck contests the theory of Gilg that the splitting of the xylem in 
leaves ( Mendoncia and Afromendoncia) is due to the penetration of 
secondary tissue derived from the cambium zone. He maintains his 
previous view that the dilatation-parenchyme has been formed on the spot 
where it exists. These conclusions are founded on observations made on 
species of Acanthaceae, Cacsalpinieae, Convolvulaceae, Bignoniaceae, and 
l\ialpighiaceae. 
* SB. Yers. Deutsch. Naturf. u. Aerzte, 1894. See Bot. Centralbl., lx. (1894) 
p. 1G7. 
f Ber. Deutsch. Bot. Gesell., xii. (1894) Gen.-Vers.-Heft, pp. 105-17. 
X Bull. Soc. Bot. France, xlii. (1895) pp. 53-67. 
§ Ber. Deutsch. Bot. Gesell., xiii. (1895) pp. 70-2. Cf. this Journal, 1894, 
p. 361. 
|| Jahrb. f. wiss. Bot. (Pfeffer u. Strasburger), xxvii. (1895) pp. 581-612 (2 pis.). 
Cf. this Journal, 1893, p. 351 ; 1894, p. 221. 
