Proceedings. 19 



Helix 'pomatia runs into many varieties, from pale straw- 

 colour to dark chestnut. 



The advantage of the colouring of the Green Tree Frog is 

 obvious to anyone who has seen one seated on the leafless 

 bough of a Fig-tree. The resemblance of the Frog to a 

 young green Fig must be a great protection from many 

 enemies. 



On an island in Lake Varese there was formerly a town on 

 piles, and flint implements may be picked up. It may be 

 noted that no flint occurs nearer than in Switzerland. 



Evening Meeting. — November 21st, 1884. 



The President exhibited a curiously spiral stalk of Asparagus 

 which grew this year in his garden at Eedhill, and was an 

 example of "fasciation" or blending of stems. 



Dr. F. Bossey read a paper on ' Atmospheric Dust as related 

 to Fermentation, Putrefaction, the Growth of Plants, and the 

 Production and Spread of Infectious Diseases,' as follows : — 



The atmosphere which surrounds our globe is loaded with 

 dust. We see this dust dancing in the sunbeam of summer, 

 and soiling the snow in winter. We inhale it with our breath ; 

 we swallow it with our food and drink. It is deposited on 

 every surface exposed to the air, and it accumulates largely 

 in all cracks, crevices, and unswept rooms. 



Among other things, this dust contains the spores or seed- 

 germs of many organised bodies. When cultivated artificially 

 or allowed to grow spontaneously, many of these germs 

 develop into minute unicellular plants or animalcules of the 

 simplest form ; but, if small in size and simple in structure, 

 these organisms are by no means wanting in power or un- 

 important in their effects. In proof of this I need only men- 

 tion that it is to some of them we owe the process of fermenta- 

 tion, by wliich we obtain our bread, as well as our beer, 

 wine, and other alcoholic drinks ; to others we are indebted 

 for the production of putrefaction, by which the carcases of 

 dead animals are removed from the surface of the earth. 

 Some, again, are the means of giving to the earth that fertility 



