333 THE JOURNAL OF BOTANY 
liquids, but permeable to water vapour. The paper was too 
apa to be reds here, and when it is Ss i it will be 
seen whether external pressure will nullify it 
Dr. E. elf then jestribed the — of ane on the 
permeability of oe A to water. n apparatus which she 
described, it had been possible to a iluerse minutely the gradual 
sai teasiics - a plant tissue undergoing plasmolysis, and then 
to determine the oui on which water passes out through the 
protoplasm by exosm By making these observations at 
different temper ary “the effect of temperature on the per- 
meability of protoplasm had been investigated. 
. M. Smith gave the last paper of a morning devoted to 
physiology, describing some rather strange = <a an investi- 
enon of the respiration of partly dried plant or, 
the afternoon there was an innovation that might well 
rio 
was possible to examine the specimens themselves, and discuss 
matters with the readers of papers, which saved a lot of useless 
questioning during a time supposed to be given over to ence. 
lt was the leananttest time of the meeting, and only marred by 
the inevitable posing to be photographed—but the sehen. of the 
photographer, and his method of address, soliaved the boredom. 
e proceedings of Friday were congested, as it was desired to 
finish the proceedings of the section on that day. Professor F.O. 
Bower gave a long paper on the phyletic arrangement of the 
Filicales, with Ee regard to the Dipterids and Pteridex. The 
paper was too full to give an account of it here; the treatment 
followed that set forth by the author in his many masterly contri- 
butions to the solving of fern problems. 
Another valuable paper followed, on the deductions to be drawn 
from the figures of rarity of the Ceylon Flora, by Dr. J. C. Willis. 
According to him the commonness of a species depends upon its 
age (in the country concerned), and local endemic species are 
simply new species in the earlier stage of spreading. From the 
fact that species of cen distribution (which must be the ‘idleat) 
increase in number the scale of commonness, whilst the 
aces (the youngest} increase downwards, and the Ceylon- 
sular-Indian species are comparatively ‘evenly distributed 
along it, such tables represent three stages in the history of a 
