BOTANICAL GAZETTE. 323 
the substance of the membranous walls I have observed numer- 
ous canals and have ascertained that they insure the continuity 
of the protoplasm through the cell walls.* 
II. The existence of these extremely tenuous canals, which 
traverse the cell walls through and through, escapes detection by 
the ordinary methods of investigation, but may be shown by the 
employment of the following methods: 
1. Photography. Thin cross sections are made of living tis- 
sues, after growth has ceased. The sections are then photo- 
graphed direct with a magnification of about 300 to 700 diame- 
ters. By using for this operation the method I have already des- 
eribed +; we obtain negatives of a peculiar interest. On these 
negatives, when examined with a lens, thecell membranes appear 
have an extremely complex structuret ; they are seen to e 
variously perforated by canals, transverse or longitudinal, which 
establish a communication between the contents of the cells.§ 
It seems impossible to ascribe this appearance of canals on the 
photographic film to any phenomenon of diffraction. 
. Direct observation. After having shown this structure upon 
my negatives, even upon old negatives which had not been made 
the microscope projected in such a way that my eye was ae 
enced only by the light proceeding from the instrument. Under 
these conditions I have succeeded in seeing Clearly the mterrup™ 
of 
Tn 1880, M. Tangl described perforations iu ~ berg cae ment hinge 3 aus 
In in my ‘‘ erches sw reil tequme se oe 
et monocotyledonous aes in Shieh the cells communicate _ hg Pe  f 
M. Strasburger, M. Russow (1882), es the albumen of 
observed in various tissues, and especially i oe aan 
similar arrangement, and have demonstrat J 
b 
0 epg Sri, vol. iil, D- 
et “a ches sur’ appareil tégumentaire deg racines, Appendix; and Revue 
Pek he munis, var. major, Ruyschia Souroubea, Clusia Liboniana, Buxus sempervirens, 
offer hese canals Gtwibte differ totally from the orl Deas in thick membranes which are 
ldagetiticum poe the defective name of a Sragrans Raphidophora pinnate | Ficus 
je oh Gang joer, Bucus sempervirens, Amorpha glabra i 
cindaspus per isus alpinus, 
é $. ifolia, Agave 
ua, Jasminum humile, Anthurium nitidum, Sm excel oa, S. rotundifi 
