ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 69 



BOTANY. 



A. GENERAL, including the Anatomy and Physiology 

 of the Phanerogamia. 



a. Anatomy.* 

 CD Cell-structure and Protoplasm. 



Part taken by the Nucleus in Cell-division.f — Herr E. Zacharias 

 states, as the result of fresh, observations, that the cell-protoplasm does 

 not penetrate into the nucleus during its division. The nucleus appears 

 to be always sharply differentiated from the cell-protoplasm when it 

 passes over into the " spindle " condition. Within the mother-nucleus 

 the groups of filament-segments of the daughter-nuclei separate until 

 they reach the poles of the mother-nucleus, and the daughter-nuclei 

 become differentiated from a central part of the mother-nucleus which 

 remains behind between them. Only the framework of the mother- 

 nucleus which contains the nuclein is completely taken up into the 

 daughter-nuclei ; a considerable portion of its matrix passes over into 

 the cell-protoplasm. Within the remains of the mother-nucleus the 

 cell-plate is formed out of the cell-protoplasm which penetrates into 

 it ; the remains of the mother-nucleus are thus increased in size, and 

 may be separated from the daughter-nuclei on both sides by cell- 

 protoplasm. 



Albumen in the Cell-waD.J — Herr G. Klebs commenting on Krasser's 

 paper on this subject and on Wiesner's previous communications, 

 contests the assertion of the former that alloxan is an unfailing test for 

 substances belonging to the group CH 2 CH (NH 2 ) C0 2 H. The utmost 

 that can be said is that certain nitrogenous substances are characterized 

 by the alloxan reaction ; it is displayed, for example, with glycocoll, and 

 to a less extent with urea and keratinin, as well as with leucin, tyrosin, 

 and other albuminoids. It is also manifested with various inorganic 

 substances, not only with ammonia, bnt w r ith potassium monophosphate, 

 sodium diphosphate, and § the bicarbonates of the alkalies. This test, 

 therefore, in no way proves the presence of albumen in the cell-wall. 

 Herr Klebs further states that if Millon's reagent is to be relied on, it 

 shows the presence of albumen in the walls of wood- and bast-cells, 

 which is incredible. 



The author also brings forward arguments in opposition to Krasser's 

 view that the cell-wall is a living organ, comparable to the nucleus or 

 the chlorophyll-bodies. The incorrectness of this view is sufficiently 

 shown by the fact that cells can be parted from their cell- walls, and 

 then have the power to form new ones. 



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

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

 Organs. 



t Versamml. Deutsch. Naturf. u. Aerzte, Wiesbaden, Sept. 21, 1887. Ber. 

 Deutsch. Bot. Gesell., v. (1887) pp. lv.-vi. 



X Bot. Ztg., xlv. (1887) pp. 697-708. Cf. this Journal, 1887, p. 981. 



