ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 585 



sulphuric acid in the cold, or if its alcoliolic solution is boiled with 

 hydrochloric or sulphuric acid, the alcohol driven off, the residue 

 treated with water, filtered, and the filtrate made alkaline, mixed with 

 Fehling's solution and boiled, the usual glucose reaction is obtained. 

 The glucose or glucose-like substance is a pale-yellow gummy 

 compound. The author, therefore, concludes that chlorophyll is either 

 a glucoside, or is associated with a glucoside. 



Cellulose accompanying the Formation of Crystals.* — A. Poli 

 has already noted f the occurrence in the pith of a number of plants 

 belonging to the order Malvaceae, of clusters of crystals attached to 

 the cell-wall by strings of cellulose. He has now examined more 

 closely the structure of these strings, and finds them to be hollow 

 tubes. They generally exhibit swellings here and there, and bright 

 refringent spots, which are probably the points of origin of new 

 crystals. Their composition is the same as that of the cell-wall, and 

 they not unfrequently become lignified in the same way. They 

 appear to occur in all the arborescent species of the order, most beau- 

 tifully in Mahaviscus mollis, but have not been observed in Malva 

 sylvestris. 



Middle Lamella of the Cell-wall.:|: — In the course of his investi- 

 gations on the continuity of protoplasm through the walls of cells, 

 W. Gardiner has investigated the structure of the middle lamella of 

 cell-walls, formerly known as " intercellular substance." He found 

 the mucilaginous degeneration of the cell-wall to be a phenomenon 

 of very frequent occurrence ; and that this mucilage is very liable to 

 be mistaken for protoplasm, owing to its being also stained by 

 Hofmann's blue. In certain cells, such as bast-prosenchyma cells of 

 the pulvini of Mimosa, and the endosperm of many palms, the cell- 

 walls consist of pure cellulose, and the middle lamella is but little deve- 

 loped ; it is more resistant, but still distinctly soluble in sulphuric 

 acid. In other instances, such as the lignified prosenchyma cells 

 of the cortex of Lycopodium, it is well defined, but lignified, like the 

 rest of the layers. In other cases it may be at once converted into 

 mucilage. The great point with regard to middle lamellas other 

 than cellulose is that in their substance the maximum amount of 

 change appears to have taken place, i. e. almost the whole of the 

 cellulose has been converted into lignin, cutin, or mucilage, as the 

 case may bo, and thus but little of the cellulose framework left. 

 This will ex})lain tlie fact that, after treatment with Schulze's mixture 

 or other oxidizing agent, the various cells readily separate from ono 

 another ; for the whole of the middle lamella has dissolved, the cellu- 

 lose framework of the cells alone remaining. It would thus appear 

 that in unaltered cellulose walls the middle lamella consists of dense 

 cellulose, while in lignified, cuticularized, corky, or mucilaginous 

 cells the changes which occur in the middle lamella are of the same 

 character as those of the rest of the membrane, and have reached 

 their maximum. 



♦ Nuov. Giom. Bot. Ital., xvi. (1884) pp. .'54-C ( 1 pi.), 

 t See this .JoiutihI, ii. (1882) p. .''.1)7. 

 i Proc. Carub. I'liil. 8oc., v. (1884) pp. 1-20. 

 Ser. 2.— Vol. IV. 2 R 



