170 ACCOUNT OF THE GENERAL AND ANNUAL MEETINGS. 
Dr. O. V. Darbishire, Ph.D., living specimens from the 
University Experimental Hothouse of Euphorbia, Cacti, and 
other succulent plants illustrative of the amount of water stored 
in the tissues. 
Mr. J. T. Kemp, example of fasciation. 
THE 45ist GENERAL, MEETING. 
November 4th, 1915. 
" Mount Vesuvius," by Prof. S. H. Reynolds, F.G.S. 
The history of this volcano was sketched from Roman times, 
and made doubly interesting by the fine series of lantern slides 
of scenery in the neighbourhood and of eruptions, with many 
details of its geology and what it revealed. 
_ Exhibits by Dr. O. V. Darbishire of dust from the last erup- 
tion of Vesuvius ; by Miss Prowse of leaves of the Canterbury 
bell showing the fibrous skeleton ; and of a jasmine plant with 
roots at parts of the stem in contact with a wall ; by Mrs. 
Knowlson of various shaped fruits of the gourd ; by Mrs. Sand- 
with of a reed warbler's nest ; by Miss Worsley of the Squirting 
Cucumber in flower and fruit; by Miss Roper of Mercurialis 
annua var. ambigua. 
THE 452ND GENERAL, MEETING. 
December 2nd, 1915. 
"Symbiosis — the Co-operative Principle in Biology," by 
Prof. Gamble, F.R.S., of Birmingham University. 
Evolution of species in the Natural world may be influenced 
by the living together of organism for mutual help as much as 
by antagonism. This occurs in different branches, as illustrated 
in the case of plants by the mycelial growth at the roots of 
poplar and beech trees, of orchids, heath, and gentians for 
obtaining a greater water supply, and giving nutriment in return, 
by the formation for nodules of animalculse on the roots of the 
pea family, and by the formation for the lichens from the 
symbiosis of alga and fungus. 
Turning to the animal kingdom, similar advantages result from 
the combination. The species of amoeba with an internal alga 
to absorb the waste nitrogenous matter gave in return a supply 
of extra oxygen, and so both organisms prospered ahead of their 
competitors. The sea anemones and corals derive the benefit of 
bright colouration from algse growing within the flesh exposed 
to light, and in like manner the green fly and certain scale 
insects have a companion to share their living state. 
Exhibits by Mrs. Sandwith of Leucadendron argenteum from 
Table Mountain ; and by Mrs. H. E. Matthews of S cilia 
autumnalis from St. Vincent's Rocks. 
Owing to the sudden death of Prof. Barrell, of the University, 
in the morning the meeting was held in the Museum Lecture 
Theatre by kind permission of the Director, Mr. H. Bolton. 
