250 SUMMARY OF CUERENT RESEARCHES RELATING TO 



causes the deposition of crystals of anhydrous dextrose. It is there- 

 fore probable that the reducing properties of protoplasm are due to 

 this glucose, and that the crystals formed with sodium chloride are 

 CeHiA, NaCl + H,0. 



This view is supported by the following experiments : — Albumin 

 (white of fresh egg) mixed with a small quantity of a very dilute solu- 

 tion of dextrose, when treated as above described, behaves in a manner 

 precisely similar to the Spirogyra cells. Moreover, if the living plant 

 is kept in the dark for a couple of days, and is then examined, none 

 of these reactions are observed. This is evidently due to the dextrose 

 being used up in the dark to nourish the cell-walls and tissues ; for, 

 after a short exposure to sunlight, the dextrose reappears, and the 

 usual phenomena are to be observed in the plant-cells. The author 

 concludes with some remarks on the aldehydic nature of dextrose, 

 on the assimilation of carbon by plants, and on the importance of 

 researches on albumin. 



Embryo-sac and Endosperm of Daphne.* — K. Prohaska brings 

 forward the structure of the embryo-sac and mode of formation of 

 the endosperm of Daphne as an illustration of the law that the polar 

 nuclei do not always coalesce to form a secondary nucleus of the 

 embryo-sac ; and that the formation of the endosperm may take place 

 without their assistance. 



The mature embryo of Daphne exhibits clearly two synergidse 

 and an ovum ; while at its lower end is a group of more than three 

 antipodal cells without any cell-wall. While the upper half of the 

 embryo-sac contains but little protoplasm, its lower portion is filled 

 with a dense mass, in which are two quite distinct nuclei with sharp 

 outline, which can be shown to be the polar nuclei. In certain young 

 states of the flower these nuclei are found in the two poles of the 

 protoplasm, which is clearly detached from both the embryonic 

 vesicles, and the antipodals; the lower nucleus subsequently approaches 

 the upper pole ; and still later, both are seen near to the embryonic 

 vesicles forming a double nucleus. This double nucleus now moves 

 gradually to the lower part of the protoplasm, which is no longer 

 distinctly separable from the embryonic vesicles ; protoplasm collects 

 round it, and the number of antipodal cells increases after fertiliza- 

 tion from 2 or 3 to 20. This double nucleus, therefore, corresponds 

 to the secondary embryo-sac nucleus of other plants. It is therefore 

 quite evident that a secondary embryo-sac nucleus is not formed after 

 fertilization by the coalescence of the polar nuclei ; but that, while 

 this double nucleus remains, the formation of endosperm commences in 

 the parietal layer of protoplasm by the free formation of nuclei. 



The following details are obtained from a number of preparations 

 of Daphne Cneorum and Blagyana. The parietal protoplasm is often 

 thickened in longitudinal threads, and contains moniliform strings of 

 vacuoles both before and at the beginning of the formation of the 

 endosperm. In it are seen small usually circular or elliptical portions 

 of denser protoplasm filled with minute granules, shown by the 



* Bot. Ztg., xli. (1883) pp. 865-8 (1 pi.). 



