ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 203 



Nutrition of the Seedling at the Expense of its Cotyledons. * — 

 G. Andre tabulates the results of determinations taken at different periods 

 after germination, of the relative weight of the seedling (i.e. of the 

 root, stem, and leaves) and of the cotyledons, in the case of Phasrolus 

 multiflorus. The results were taken at five intervals, respectively 9, 11, 

 13, 15, and 17 days after the commencement of germination. At the 

 last period the weight of the ashes of the cotyledons was not more than 

 two-fifths of that of the seed. The tables show the relative rapidity 

 with which the various mineral ingredients were withdrawn from the 

 cotyledons by the growing seedling. The fatty matters disappear 

 gradually from the cotyledons, while the soluble carbohydrates are 

 absorbed rapidly during the early stages of germination, as also do 

 those which are converted into sugar by dilute acids. The mineral 

 matters are never completely absorbed. 



Necessity of Lime for Plants.f — L. Ritter v. Portheim disputes the 

 statement of previous observers that, at a high temperature, lime is not 

 necessary for the germination of seedlings. He found the contrary to 

 be the case with the species experimented on, viz. : — Lepidium sativum, 

 Rumex Acetosella, Secale cereale, Hordeum, Triticum, Avena sativa, Larix 

 europsea, and Pinus sylvestris. The absence of lime produces all the 

 symptoms of poisoning caused by the great accumulation of acid 

 potassium oxalate when no calcium salt is present. 



Influence of Mineral Salts on the Production of Root-tubercles in 

 Pisum. — As the result of a series of experiments on growing a variety 

 of the garden pea in soils of different compositions, E. Marcbal J finds 

 a confirmation of the view that their formation is dependent on a defi- 

 ciency of nitrogen in the soil. The presence of alkaline nitrates to the 

 extent of 0*01 p.c' prevents the formation of the tubercles; salts of 

 ammonium, in the proportion of 0'05 p.c, Lave the same effect ; as also 

 have salts of potassium to the amount of 05 p.c, and of sodium to 

 • 33 p.c. On the other hand, salts of calcium and magnesium promote 

 the formation of the tubercles ; and this is also usually the case with 

 phosphoric acid, though dependent on the base with which it is com- 

 bined. 



Similar results were obtained by E. Laurent, § except that, in the 

 case of Faba, nitrogenous manures were found to promote, instead of to 

 hinder the production of tubercles. 



Action of Copper on the Growth of Living Cells. || — D. Miani has 

 experimented on the effect produced on the germination of pollen-grains 

 and fungus-spores by contact with the water in which they germinate of 

 coins or some other form of metallic copper. If the cuprification of 

 the water is only very slight, the effect on germination is a decidedly 

 favourable one, germination taking place more rapidly, and the pollen- 

 tubes being better developed. If the surrounding air is saturated with 

 moisture, it is not necessary for the copper to be actually in contact 

 with the hanging drop in which the pollen-grains germinate. The 

 pollen experimented on belonged to a number of different species. 



* Comptes Kendus, cxxxiii. (1901) pp. 1011-3, 1229-31. 



t Sitzungsber. k. Akad. Wiss. Wien, ex. (1901). Scl- Bot. Centralbl., lxxxviii. 

 (1901) p. 282. t Comptes Rendus, cxxxiii. (19(H) pp. 1032-3. 



§ Tom. cit., pp. 1241-3. || Ber. Deutsch. Bot. Ges., xix. (1901) pp. 461-4. 



