758 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



BOTANY. 



A. GENERAL, including the Anatomy and Physiology 

 of the Phanerogamia. 



a. Anatomy.* 

 CD Cell-structure and Protoplasm. 



Action of basic substances on living Protoplasm.f — ITcrr T. 

 Bokorny has iuvcstigatcd the action of a number of difforcnt basic siib- 

 stances on living protoplasm. In all cases they agree with the action of 

 ammonia in causing granulation botli in the protoplasm and in the cell- 

 sap. Experiments were made with the following substances : — potassa, 

 soda, ° amine-bases, diamide or hydrazin, hydroxylamin, strychnine, 

 chinine, atropine, vcratrine, chinolinc, and caffeine. 



Forms of Cells. J — Prof. L. Errcra offers a mathematical explanation 

 of the various forms assumed by vegetable cells, from the corresponding 

 phenomena observed in the blowing of soap-bubbles. 



Physiology of the Cell.§ — Herr G. Klebs has collected his recent 

 observations on various points in the structure of the cell, adding also 

 some fresh ones. 



Alf^aj, leaves of mosses, and similar structures, can be preserved in a 

 living condition in solutions which afford a supply of nutriment, to which 



• 05 per cent, of normal potassium chi'omate has been added. 



The author describes the artificial fresh formation of the cell-wall 

 after plasmolysis in concentrated solutions of cane-sngar and glycerin. 

 This takes place with Vaiicheria within an hour, in most other algae after 



1 or 2 days. A similar formation of cell-wall after plasmolysis takes place 

 also with some leaves of mosses, and prothallia of ferns, and with leaves 

 of Elodea canadensis ; but was not observed with desmids or diatoms, or 

 with the tissues of dicotyledonous plants. The formation of the new 

 cell-wall is best exhibited by the use of congo-red. In a 1 per cent, 

 solution of sugar coloured by congo-red, the first formation of the cell- 

 wall could be detected in opened tubes of Vaiicheria. The author does 

 not af^ree with do Vries that the parietal utricle has the special faculty 

 of forming cellulose ; it belongs, on the contrary, to every part of the 

 protoplasm. It was distinctly seen that the growth of the new cell-wall 

 takes place by apposition. In Zygnema also he found no evidence of 

 growth by intussusception. 



The growth and division of protoplasts was observed in CEdogonium, 

 Cladopliora, and other objects plasmolysed in a concentrated solution of 

 sugar. Growth of the protoplasts and formation of starch may take 

 place in the dark, but apparently not division. Portions of the protoplast 

 which contain no nucleus can assimilate and form starch, but appear to 

 have no power of growing or forming a new cell-wall. 



A peculiar degradation of the chlorophyll-bodies was observed in 



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

 contents (including Secretions); (3) Structure of Tissues; and (-1) Structure of 

 Organs. 



t Pringsheim's Jahrb. f. Wiss. Bot., xix. (1888) pp. 206-20 (1 pi.). 



X Versamml. Deutscher Naliurf. u. Aerzte, Wiesbaden, Sept. 21, 1887. See Bot. 

 Centralbl., xxxiv. (1888) p. 395. 



§ Untc-rs. Bot. Inst. Tubingen, ii. (1888) pp. 489-568 (2 pis.). See Bot. Centralbl., 

 xxxiv. (188S) p. 228. Cf. this Journal, 1887, p. 254. 



