INTERCELLULAR RELATIONS OF PROTOPLASTS. 
121 
ON THE INTERCELLULAR RELATIONS OF 
PROTOPLASTS.—ID* 
BY WILLIAM HILLHOUSE, B.A., F.L.S., 
PROFESSOR OF BOTANY AND VEGETABLE PHYSIOLOGY AT THE MASON SCIENCE 
COLLEGE, BIRMINGHAM. 
(Continued from page 105.) 
The method of development of the sieve plate and its 
perforations affords still disputed ground in several particulars. 
The partition wall is at first single and homogeneous, but, 
according to Russow, prior to the appearance of the callus is 
already punctate in that portion of its membrane where the 
sieve area will be formed, while Wilhelm and Janczewski 
maintain that the punctation does not appear till after the 
callus formation. Very early the area is covered on both sides 
PLATE III. 
DESCRIPTION OF THE FIGURES. 
Fig. 1.—Terminal sieve plate of Bryonia dioica, in transverse section 
of stem. 
Fig. 2.—Terminal sieve plate of Bryonia dioica , in radial longitudinal 
section of stem, very greatly swollen with Russow’s Aniline Blue, but 
showing strongly-marked sieve canals. The remains of the original 
sieve plate wall are still visible, though very indistinctly, not quite so 
clearly as in the figure. 
Fig. 3.—Terminal sieve plate of Bryonia dioica , in longitudinal radial 
section of stem, also treated with Aniline Blue, but much less swollen 
that that in Fig. 2. Protoplasmic threads, few in number, can be seen 
passing to and through the plate. 
Figs. 1-3 were drawn from sections taken from alcohol material 
gathered in August. 
Fig. 4.—Terminal sieve plate of Cucurbita Pepo, in longitudinal 
radial section of stem, showing the mucous collection on each, but 
mostly on one side of the sieve plate, traversed by strands which also 
pass through the sieve perforations. Taken from alcohol material of 
July, 1881, the section having been now two years mounted in 
glycerine, stained Logwood. The protoplasmic mucous is of a dirty 
pale-brown colour, and the threads show more plainly than depicted 
in the figure. 
Fig. 5.—Sieve plates of Cytisus Laburnum in longitudinal tangential 
sections of stem, after 24 hours in Potassium Iodide Iodine, and previous 
treatment with Chlorzinc Iodine. December. 
Fig. 6. —Sieve perforation in Cytisus Laburnum , after staining with 
Alcohol Iodine and removal of the walls by 48 hours in strong Sulphuric 
Acid. July. 
* Transactions of the Birmingham Natural History and Micro¬ 
scopical Society. Read March 18th, 1884. 
