666 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of the plant to another. Daring the brief duration of a summer night 

 the whole of the starch accumulated during the day in the large leaves 

 of Helianthus and Cucurbita passes through the leaf-stalk into the 

 stem. Researches into the rapidity of diffusion show that if this pro- 

 cess were the sole cause of the movement it would take months or 

 even several years to accomplish. The author is of opinion that it 

 is effected mainly by the rotation and circulation of the protoplasm. 



In order to determine the wide distribution of these phenomena, 

 the author subjected a number of plants to examination. In Trades- 

 cantia rosea he found these movements in the conducting cells of the 

 phloem of the vascular bundles; in this instance a true rotation 

 passed up one longitudinal wall of the cell and down the other vp^all, 

 the movement being at the rate of • 2-0 • 4 mm. per minute. The 

 movement was observed in the young half-developed branches, in all 

 the internodes of the stem, in the central veins of the leaves and of 

 the leaf-sheath, and in the rhizome and roots, always in the paren- 

 chymatous cells, the rotation of the protoplasm carrying with it the 

 microsomes, chlorophyll-granules, and starch-grains. A movement of 

 circulation was equally universal in the epidermal cells of all organs, 

 and one of rotation in the xylem-cells and in the young, thin-walled, 

 but very elongated elements of the stiffening-ring. 



Similar phenomena were observed in Tropceoleum majiis, Cucurbita 

 Pepo, JElodea canadensis, Hydrocliaris morsus-rance., and Limnocharis 

 Humbuldtii, in some cases also in the young bast-fibres, the wood-cells, 

 and the epidermal cells ; all intermediate stages being noted between 

 typical rotation and circulation. The movement is, however, most 

 easily seen in the conductiag-cells of the phloem. 



The author concludes that movement of the protoplasm is a uni- 

 versal phenomenon in tissues adapted for the accumulation and 

 conduction of food-material ; and that the protoplasm, not only in 

 special cases or during particular periods of life, but everywhere and 

 so long as it is active, has portions which are in motion. 



Division of the Cell-nucleus in Plants and Animals.* — M. L. 

 Guignard continues his researches on this subject, and has further 

 established the identity of the process of indirect division in the two 

 kingdoms. He finds the highest of the vegetable types, and the one 

 which displays most completely the analogy with the animal kingdom, 

 in the nucleus of the embryo-sac of Lilium candidum. 



The nucleus is composed of a single filament, the folds of which 

 frequently anastomose to form a network ; and the author considers 

 that the difference on this point between the views of Prof. Strasburger 

 and M. Flemming is apparent rather than real. The granulations or 

 chromatic microsomes are arranged in a single row in the hyaloplasm 

 of the filament. Their size varies not only in different filaments, but 

 even in the same. 



The nucleoli, from their first appearance, present distinct 

 reactions, showing that their chemical composition differs from that 



* Ann. Sci. Nat.— Bot., xx. (1885) pp. 310-72 (4 pis.). See this Journal, iii. 

 (1883) p. 86-1 ; iv. (1884) p. 915. 



