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dants attached to the links. Each character of an animal or plant 
may be attributed to two factors, “ nature,’ which can be trans- 
mitted, and ‘“‘ nurture,’ which cannot be. Breeders improve their 
stock by selecting variations, not by nurturing individuals. 
The lecturer next dealt with the work of Mendel in heredity. 
Describing Mendel’s experiments in hybridising peas, he showed 
how on certain hypotheses the results may be accounted for. Still, 
the origin of characters was as complete a mystery as ever. The 
merely negative proposition that they do not originate as the 
direct effect of use being all that has been established. 
Friday, May 11th. Sir Samuel Wilks, Bart., F.R.S., in the 
Chair. There was a large attendance. This meeting was devoted 
to blackboard demonstration. 
Mr. Hugh Findon, F.L.S., showed **‘ How Pond Mussels 
Breath Air.’’ By means of diagrams in chalk of sections of 
the gills of Anodon cygnea, he demonstrated how the air passed 
from the aerated water through the tissue of the branchie to the 
hemolymph, or colourless blood of the animal, and also the action 
by which a constant stream of fresh water is caused to flow past 
one side, to penetrate the curtain of gills, and to be ejected from the 
shell again. The actual gills of preserved specimens were exhibited 
for members to examine their structure. 
Miss Garlick gave a demonstration on ‘* Useful and 
Interesting Plants of the Natural Order Myrtaceex.” In 
this order the seed vessel is joined to the calyx-cup and the stamens 
start from the ring which borders the cup. The calyx-lobes form 
a crown to the ripe fruit. To this order belong the pomegranate, 
guava, allspice, clove, etc. In the clove, the flower bud, which 
we use as spice, shows clearly the relative positions of calyx-lobes 
and seed vessels, but the stamens are enclosed in the folded petals 
and seldom observed. 
In eucalyptus flowers the part of the calyx unattached to the 
seed vessel separates horizontally and comes off like a lid when 
the flower is mature. Such horizontal fission is unusual, but 
another example is furnished by the fruit of Bertholittia excelsa 
of the allied order Lecythidee, the seeds we call Brazil nuts. This 
fruit is round, about six inches in diameter, its woody shell is 
half-an-inch thick, and contains one to two dozen seeds round 
a woody axis. 
Miss Garlick exhibited the stems, leaves, buds and fruit of 
clove ; branches of eucalyptus, with buds, flowers and fruit; and 
the fruit and seeds of Bertholittia. 
