ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 167 



BOTANY. 



A. GENERAL, including the Anatomy and Physiology 

 of the Phanerogamia. 



a. Anatomy. 

 (1) Cell-Structure and Protoplasm. 



Attractive Spheres in Angiosperms.* — Ch. Bernard confirms, in a 

 general way, the observations of Guignard and others with regard to the 

 occurrence of attractive spheres in the plants observed — chiefly Lilium 

 candidum and Helosis guayanensis (Balauophoracese) ; but finds them 

 much less sharply defined and less easy to detect than has been stated 

 by others. Around the nucleus is an accumulation of very dense and 

 very granular protoplasm, the kinoplasm of Strasburger. This is the 

 seat of the attractive spheres. The centrosome may be wanting, or at 

 least may not be visible. The size of the spheres is variable, and their 

 outline badly defined. The number of centrosomes also varies. The 

 author agrees with Guignard in tracing the spheres to a cytoplasmic 

 origin. 



In both the species named, a double embryo-sac was occasionally 

 observed. 



As a fixing material, the author used Flemming's mixture. The 

 best staining results were obtained with a mixture of 1 part aqueous 

 solution of 1 p.c. fuchsin, 2 parts aqueous solution of 1 p.c. iodine-green, 

 and 40 parts water. 



A good bibliography is appended to the paper, and it commences 

 with a critical survey of existing literature. 



Dimorphism of Protoplasmic Connecting Threads, f — F. G. Kohl 

 points out that the protoplasmic connections between cell and cell of a 

 tissue are of two kinds, between which there are scarcely any inter- 

 mediate conditions : — either the connecting threads perforate only the 

 membrane of the pits, when they may be termed aggregate threads, or 

 they perforate solitarily any portion of the cell-wall. It is rare for both 

 kinds of connection to concur in the same tissue and the same cell. 

 The endosperm of Chamserops excelsa presents, however, an exception 

 to this rule. In the peripheral cells the connecting threads are chiefly 

 or exclusively solitary, while in the central cells they are both solitary 

 and aggregate. The swollen knots which are seen on solitary connecting 

 threads are for the most part artifacts. The swelling of the membrane 

 which lies outside a pit must proceed very uniformly in the separate 

 layers ; for the solitary connecting threads which perforate them are 

 usually without such swellings. The bendings of the threads which 

 perforate the margin of the pit-membrane are not a result of the swel- 

 ling of the membrane ; the latter causes rather a flattening of these 

 bendings. 



In the endosjierm-cells of many palms the protoplasmic threads tate 



- Journ. de Uot. (Morot), xiv. (1900) pp. 118-24, 177-SS, 20(3-12 (2 pis.). 

 + Ber. Deutscb. Bot. Ges., xviii. (l'JOO) pp. 364-72 (1 pi.). 



