ME. S. LE M. MOORE's STUDIES IN VEGETABLE BIOLOGY. 593 



Studies in Vegetable Biology.— I. Observations on the Con- 

 tinuity of Protoplasm. By Spencer Le M. M&6re, F.L.S. 



[Read 2nd April, 1885.] 

 (Plates XIX.-XXI.) 



Continuity; of protoplasm, other than through the sieves of 

 sieve-tubes, was first announced in Phanerogamia by Dr. Tangl *, 

 in his well-known study of the eudosperm of Strychnos Nux- 

 vomica and certain palms, It is not my intention to quote the 

 bibliography of a subject which has so fascinatingly influenced 

 authors that a large number of memoirs have alread} r been pub- 

 lished upon it ; it will suffice here to refer to Messrs. Schaar- 

 schmidt'st and Gardiner's \ recent papers, wherein ample 

 bibliographical details will be found. 



It will be remembered that Tangl discovered the thick un- 

 pitted walls of the large cells forming the main mass of the 

 endosperm of Strychnos Nux-vomica to be penetrated by threads 

 of protoplasm, which join similar threads runuiug through con- 

 tiguous cell-walls, whereby the protoplasm of each cell is placed 

 in communication with that of its neighbours. This structure is 

 not to be seen in sections treated with water, a medium which 

 causes strong swelling of the walls, accompanied by their stria- 

 tion, and the differentiation of the layers of thickening into an 

 outer and an inner zoue. After the action of dilute alcohol upon 

 dry sections, or, better, of iodine in slightly diluted alcohol, or 

 in potassium iodide, with or without subsequent treatment with 

 chloriodide of zinc, the groups of connecting threads are easily 

 to be seen with moderate powers, the outer threads of each group 

 bowed, the middle ones straight, somewhat after the fashion of 

 the strings of a mandolin. A bird's-eye view of the wall shows 

 that it is uniformly perforated by crowds of small round openings. 

 Minute examination led Tangl to conclude that these openings 

 are entirely occupied by protoplasm, whose inability to take up 

 colouring-matter shows that it is referable to the limiting layer 

 (Hautschicht), a structure well developed in these cells. The 

 walls of the epidermis and immediately underlying thin-walled 



* Pringsheim's Jahrb. f. Wiss. Bot., Band 12 (1879). 



t ' Nature," 1S85, Jan. 29th. \ ' Nature,' 1885. Feb. 26th. 



