Physiological Studies in Plant Anatomy 257 
splitting of the wax surface. It seems evident that with complete 
exclusion of air no suberisation would occur. 
On March 7th cut surfaces of a begonia stem were similarly 
covered with gelatin. Examined on March 23rd, suberisation had 
occurred to a considerable extent 
though perhaps not so freely as 
at the completely exposed sur¬ 
face. But a gelatin film could not 
be expected to keep out the air rX/ 
in the same manner as a film of 
paraffin wax. Meristem forma- 'Jb, 
tion had begun in both cases. 
Glass Tube 
V^ter Level. 
Stems covered with gelatin in 
this manner on March 7th were 
re-examined on May 23rd. In 
this case there was clearly both a 
larger amount of suberisation and 
a more active meristem present 
on the freely exposed wound sur¬ 
face than on the one covered with 
gelatin. 
On March 7th an exposed cut 
surface was partly covered with 
distilled water in the manner 
shown in the diagram (Text-fig.). 
The water was renewed daily to 
avoid the development of disease 
as far as possible. The cut surface 
was examined on March 19th 
and more suberisation had oc¬ 
curred on the surface of the cut 
above the water, only a slight 
indication of suberisation being 
obtained in the superficial cells 
covered by the water. As no 
meristem had yet formed, the 
experiment was repeated, in this case the cut surface extended below 
the base of the tube as well as above the water in the tube. The 
experiment was started on March 18th and stopped on April 6th. The 
cut surface both above and below the water showed much suberin 
deposited and the presence of a meristem. In the region under 
- --Ste* 
—Cotton Wool. 
Wound 
