IX VEGETABLE BIOLOGY. 617 



with the contour of ordinary rings ; but upon this ground there 

 is as much reason for regarding crystalloids not to be of proto- 

 plasmic nature as these ring-contours. It is only in the wide 

 sense which modern research has giveu to the conception of pro- 

 toplasm that I wish to be understood when referring the compo- 

 sition of the rings to that substance. 



Postscript. — As tending to confirm the conclusions arrived at 

 from the necessarily incomplete study of development contained 

 in the foregoing pages, it would have been advisable to quote in 

 more detail Mr. Massee's beiore-mentioned paper on " Polysi- 

 phonia (fastigiata and urceolata)" in the ' Journal of the Royal 

 Microscopical Society ' for 1884. Massee's method was to re- 

 move the wall from cells near the growing-point by soaking for 

 several hours in a solution of nitro-picric acid. By this means 

 it was found that the young protoplasts are connected by fine 

 marginal threads, as well as by a thicker central band of proto- 

 plasm, and that, with the exception of an aperture for the passage 

 of the latter, the protoplasts become isolated by the gradual de- 

 velopment of a cell-wall between them. The aperture increasing 

 in size with the growth of the cell, is after a time, spanned by a 

 sieve-plate, which, as already stated, this author considers to be 

 composed of cellulose. 



Reference should also be made to Mr. Hick's recent paper 

 ('Journal of Botany,' April 1883) on Continuity in several 

 species of Fucus. By the employment of a number of refined 

 processes, Hick has satisfied himself that continuity throughout 

 the tissues of these types may obtain in either of four ways :— (i.) 

 Through a comparatively wide and open pore ; (ii.) by the inter- 

 position of a sieve-like diaphragm ; (iii.) by means of a single ribbon 

 of protoplasm passing through a longand narrow slitinan otherwise 

 impervious diaphragm ; (iv.), as (iii.), but the ribbon reduced to a 

 mere filament transmitted through a minute pore in the diaphragm. 



DESCRIPTION OF THE PLATES. 

 Plate XIX. 

 Fig. 1. An endosperm-cell of Strychnos Ignatia swollen up in water, (k in 

 this and the following figures marks the primary wall of the cells.) 

 X450. 



2. Piece of endosperm of the same treated with solution of iodine in alcohol 



and then with a small quantity of water. X 000. 



3. The same, but after addition cf water, showing nodules upon (lie intra- 



mural threads. X 000. 



