168 SUMMARY OF CURRENT RESEARCHES RELATING TO 



a deep stain from methyl-violet, saffranin, or brilliant-blue, without any- 

 previous fixing, and remain perfectly homogeneous. 



First Mitosis of Spore-mother-cells of Lilium.*— Dr. H. H. Dixon 

 has made a study of this subject for the purpose of determining the 

 sequence of processes in the mitotic division of the nucleus. The stages 

 in the process in which all observers are agreed are recounted in detail. 

 "With regard to the early stages, the author states that a careful study 

 of the process in the pollen-mother-cells and embryo-sac of Lilium longi- 

 florum has led him — contrary to the opinion of most observers — to 

 regard the strepsinema or second stage as probably arising from the 

 looping on each other and approximation of two portions of the thread 

 in its first or dolichematous stage. The reasons for adopting this view 

 are given in detail. In the next stage the double thread is broken up 

 into a number of chromosomes, each composed of two portions twisted 

 and looped together. The author does not believe that the first mitosis 

 of the spore-mother-cells is a differential or "reducing" division. The 

 two daughter-nuclei receive half of each primary chromosome, which is 

 itself a segment of the original dolichonematous thread. 



Hardness of Vegetable Membranes, f — According to Emma Ott, 

 vegetable membranes, tried by the test of scratching, exhibit, when 

 freed from mineral substances, a smaller variation in their hardness than 

 has generally been supposed. They range, as a rule, in the second grade, 

 being somewhat harder than muscovite, but scarcely scratching rock-salt. 

 When the apparent hardness of a vegetable membrane is much higher 

 than this, it is always due to the presence of a larger or smaller quantity 

 of a mineral deposit, most commonly silica. The pericarp of Coix 

 lachryma has a hardness of seven. The ash of Equisetum maximum con- 

 tains as much as 70* C4 p.c. of silica. 



Shrinking of the Cell-wall.} — C. Steinbrink gives formulas for the 

 energy of transpiration, and further discusses the effect on transpiration 

 of the permeability of the cell-wall, and the effect of increased tran- 

 spiration as a hindrance to the shrinking of the cell-wall. 



(2) Other Cell-contents (including: Secretions). 



Composition of Aleurone-grains § — According to A. Tschirch and 

 H. Kritzler, the aleurone-grains of seeds consist mainly of globulins 

 similar to those of animal proteids. The crystalloids contain at least 

 two globulins. Aleurone-grains contain also possibly small amounts of 

 albumose. The globoids contain protein (globulin), calcium, magnesium, 

 and phosphoric acid. The germinating power of seeds probably depends 

 directly on the solubility of the crystalloids in dilute sodium chloride 

 solution. The oil of seeds is not present in the form of drops, but is 

 mixed with the cell-plasma in the form of oleoplasm ; the aleurone- 

 grains contain no oil. 



* Proc. R. Irish Acad., vi. (1900) pp. 1-12 (2 pis.). 



t CEsterr. Bot. Zeitschr., 1. (1900) pp. 237-41. 



I Ber. Deutsch. Bot. Ges., xviii. (1900) pp. 386-96. 



§ Ber. Deutsch. Pharm. Ges., x. (1900) pp. 214-22. See Journ. Chem. Soc, 1901, 

 Abstr. ii. p. 33 ; also Kritzler, Microchem. Unters. iib. d. Aleuronkorner, Bonn, 1900, 

 80 pp. and 2 pis. See Bot. Ztg., lix. (1901) 2" Abt. p. 74. 



