98 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



tliat, when fresh-gathered, they contain about 9 per cent, of water, 

 6 per cent, of nitrogen, and 4 per cent, of ash ; or'more exactly, after 

 drying, 31 '63 per cent, of nitrogenous substances, 64*36 of non- 

 nitrogenous substances, and 4-01 per cent, of ash. Among nitro- 

 genous substances, Dr. de Planta has determined the presence of 

 globulin, peptones, hypoxanthin, and amides. The presence of 

 saccharose was also ascertained, while glucose is absent. The sugar 

 contained in pollen-grains is therefore not directly capable of assimi- 

 lation ; the proportion of cane-sugar is as much as from 7 to 8 per 

 cent. Starch is also present to the extent of more than 5 per cent. 



In the pollen of the hazel the author found in addition colouring 

 matters of two kinds, one easily soluble in water, the other only with 

 difficulty ; cuticule, about 3 per cent. ; waxy substances not definitely 

 identified ; fatty acids, about 4 per cent. ; cholesterin ; and a bitter 

 resinous substance. 



Ovum-cells and Antherozoids.* — By the examination of the ovum- 

 cells and antherozoids of CJiara, mosses, and ferns, spermatozoids of 

 frogs, and the ovum-cells and pollen-tubes of flowering plants, Herr 

 E. Zacharias has satisfied himself that the male sexual cells are dis- 

 tinguished by the small size or entire absence of nucleoli, and the 

 abundant nuclein ; the nuclei of the female cells containing but very 

 little nuclein, abundance of albuminoids, and one or more nucleoli, 

 often of great size. These nucleoli are not distinguishable in their 

 chemical properties from those of other nuclei ; the cell-protoplasm 

 contains no nuclein. It follows that the fertilized ovum-cell must 

 contain more nuclein in proportion to its other constituents than 

 before fertilization. 



"Luminous Line" in the Seed of MalpigMacese-t — Sig. O. 

 Mattirolo attributes to the presence of lignose the peculiar appearance 

 known as the "luminous line " in the sclerenchymatous layer of ihe 

 integument of the seed of Malpighiacese, the phenomenon correspond- 

 ing, therefore, to that in other nearly allied orders, as the Tiliaceae. 



Seminal Integuments of Tiliaceae.^ — Sig. 0. Mattirolo describes 

 in detail the structure of the seed in several species of Tilia and 

 Corchorus, and in Sparmannia africana. In the course of development 

 of the seed, the integument becomes differentiated into two well- 

 defined layers, the outer layer being composed of what the author 

 terms " Malpighian cells." Through this layer runs the peculiar 

 "luminous line" characteristic of the seeds of Tiliacese, and which 

 Sig. Mattirolo determines, by the application of a great variety of 

 reagents, to be due to the peculiar modification of cellulose known 

 as lignin. 



Suberification in the Seminal Integument of Tilia.§ — Sig. 0. 

 Mattirolo describes the following processes as taking place in the 

 development of the seeds of Tilia : — A gradual transformation by 

 which the cells full of protoplasm lose their power of division ; their 



* Ber. Deutsch. Bot. Gesell. Generalvftrsammlung, 1885, p. Ixv. 

 t Mem. R. Accad. Sci. Torino, xxxvii. (1885) (1 col. pi.). 

 % Nuov. Giorn. Bot. Ital., xvii. (ISSS) pp. 289-319 (3 pis.). 

 § Atti R. Accad. Sci. Torino, xx. (1885) pp. 116G-72. 



