78 SUMMARY OP CURRENT RESEARCHES RELATING TO 



BOTANY. 



A. GENERAL, including the Anatomy and Physiology 

 of the Phanerogamia. 



o. Anatomy.* 

 Q) Cell-structure and Protoplasm. 



Movement of Rotation of Vegetable Protoplasm.! — M. J. B. 

 Sclmetzler has recently studied the rotation of the protoplasm in aa 

 elongated protonemal cell of Chara fragilis. The grains of chlorophyll 

 develope first in the upper part of the cell, while the lower part is 

 filled with colourless protoplasm. On the interior of the cell- wall a thin 

 motionless layer of protoplasm is differentiated ; the chlorophyll-grains 

 being fixed on the inner face of this layer. In the interior of this inert 

 protoplasm will be found a comparatively thick layer of protoplasm 

 which executes the movement of rotation. 



Protoplasmic Movements.:]: — Dr. J. Clark has investigated the 

 influence of the lowered oxygen pressure on protoplasmic movements. 

 A great number of vegetable organisms with streaming protoplasmic 

 movements were experimented with. The removal of oxygen brings the 

 movement to a standstill ; the return of the natural conditions immedi- 

 ately brings back the circulating phenomena. A pressure of 1 • 2 mm. of 

 oxygen restored the movement in Triania hogotensis ; a pressure of 

 2 • 8 mm. was required for the hairs of Urtica americana ; the other 

 cases lie between these two extremes. The experiments with ciliary 

 action have been already referred to.§ 



Optical Properties of the Cuticle and of Suberized Membranes. || — 

 Hcrr H. Ambronn shows that while suberized membranes, as observed 

 by Dippel, exhibited a change in their optical axes on treatment with 

 potash, they can be made optically neutral by simply warming in water 

 or in dilute glycerin. From this fact he infers the presence in the 

 cell-walls of a substance which melts at the temperature of boiling water 

 and again crystallizes on cooling. This must obviously be either a 

 waxy or a fatty substance. 



(2) Otlier Cell-contents (including Secretions). 



Structure of Chlorophyll-grains.H — Herr A. Meyer replies to 

 Schwarz's criticisms ** on his views as to the structure and development 

 of chlorophyll-grains. After repeating his observations with the 

 greatest care, he asserts that Schwarz's account of the structure of 

 chloroplasts, that they consist of green " fibrillas " lying side by side, 

 united together by an intermediate substance " metaxin," is founded 

 on error. By continuous and careful observation of the action of water 

 on a single chloroplast, he was never able to detect anything approaching 

 to fibrillar structure. 



* This subdivision contains (1) Cell-structure and Protoplasm; (2) Otlier Cell- 

 contents (including Stcretions) ; (3) Structure of Tissues ; and (4) Structure of 

 Organs. t Bull. Soc. Vaud. Sci. Nat., xxiv. (1888) pp. 83-8. 



% Ber. Deutsch. Bot. Gesell., vi. (1888) pp. 273-80. 



§ See this Journal, 1888, p. 971. 



il Ber. Deutsch. Bot. Gesell., vi. (1888) pp. 226-30. Cf. this Journal, 1888, p. 602. 



i Bot. Ztg., xlvi. (1888) pp. 636-40. ** See this Journal, 1887, p. 979. 



