ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 49 



of the multipolar spindle in Gladiolus, which furnishes a good material 

 for study of nuclear phenomena, from the large size of the anthers, pollen 

 mother-cells, and nuclei. 



As nuclear division approaches, a granular zone accumulates about 

 the nucleus. This zone resembles in every respect the perikaryoplasm 

 characteristic of the pollen mother-cells of Cobsea* A close network 

 or felted zone of kinoplasm fibres is formed immediately outside and 

 completely surrounding the nuclear wall ; this is probably developed 

 from the perikaryoplasm. This network grows out into several pro- 

 jections which become the poles of the multipolar figure. The nuclear 

 membrane persists until the cones are nearly fully developed. The 

 spindle-fibres are formed by the elongation of the meshes of the network 

 composing the cones. Neither the nuclear wall, the nucleole, nor the 

 linin, takes any essential part in the formation of the achromatic figure. 

 The cones of the multipolar figure fuse, and arrange themselves in two 

 groups, forming a bipolar spindle. 



Formation of Vacuoles. \ — In order to determine the question 

 whether vacuoles have a well-defined tonoplast or not, Dr. B. Neinec 

 incited in the cytoplasm the artificial formation of soluble bodies, round 

 which vacuoles developed. Nucleole-like bodies may arise in this way 

 in the meristematic cells by the operation of various injurious agencies. 

 When the meristem of a root-apex is plasmolysed, in about 25 mins. 

 " nucleoles " are seen in the cytoplasm after the material has been fixed 

 and sectioned ; after about 30 mins. the vacuoles begin to make their 

 appearance round them ; and after 40-45 mins. nothing is to be seen 

 except the vacuoles without any contents. 



Membrane of Hydroleucites. J — V. Boulefc supports de Vries's and 

 Went's contention that the vacuole or hydroleucite in living cells is 

 an organised structure enclosed in a distinct membrane, the tonoplast. 

 When plasrnolysed by the action of potassium nitrate, the protoplasm 

 contracts in a regular manner round the hydroleucite into a spherical or 

 ellipsoidal mass, and the chloroleucites are massed together generally 

 at one of the poles. At a more advanced stage of disorganisation, the 

 hydroleucite appears to fill up the whole of the cell-cavity, pressing 

 against its walls the debris of the protoplasm and the chloroleucites 

 which are profoundly changed. The crystals are always localised in 

 the hydroleucite, and appear to be unable to escape into the protoplasm, 

 from which they are separated by an invisible membrane not belonging 

 to the protoplasm. 



Permeability of the Cell-wall for Air. § — C. Steinbrinck discusses 

 the question whether the permeability of the cell-wall for air is a hind- 

 rance to its shrinking, and, as the result of a series of experiments on 

 different plants and various tissues, concludes that there is no connection 

 between the two phenomena. 



* Cf. this Journal, 1900, p. G85. 



t S.B. k. Bohm. Ges. Wiss. (Math.-uatunv. CI.), 1900, No. 5. See Bot. Centralbl.. 

 Ixxxiv. (1900) p. 163. 



X Rev. Gen. de Bot. (Bonnier), xii. (1900) pp. 319-22 (3 figs.). 

 § Ber. Duutsch. Bot. Ges.. xviii. (1900) pp. 275-85. 



Feb. 20th, 1901 E 



