BIRMINGHAM MICROSCOPICAL SOCIETY. 307 
Indeed, it is a fact, as proved by my study of Dendrosoma alone, 
that if these things can by any means be kept in active life, it only 
needs careful observation to unfold their history with all its interest 
and absorbing attractiveness. 
I have not wondered that many naturalists have from time to 
time spoken in high satisfaction of their success in maintaining and 
increasing their stock of such things as Melicerta and even Volvox, 
with other organisms of like interest, and am free to confess that 
my own indoor aquaria have assumed a very abnormal, not to say 
obstructive, growth, often proving successful, however, far beyond 
my expectation. But I have found that, with all ordinary care, the 
creatures and plants too are stimulated into such rapid changes that 
sooner or later they come to grief, if I may use that expressive 
sporting phrase, and that one needs to begin over and over again. 
Now I was under considerable doubt as to whether a small pond 
constructed in my garden would be sufficiently successful to repay 
the somewhat heavy cost; whether the inevitable town surroundings 
of bricks and mortar, and the accompanying smoky and often dusty 
atmosphere would not overcome anything I might do in providing 
other more favourable conditions for the existence of these delicate 
organisms, and I am pleased, therefore, to be able to say that the 
plan has answered admirably, and that, in addition to the microscope 
and the complement of books which a student needs, I most 
earnestly commend all lovers of this study to acquire a garden-pond. 
My own has not only furnished me with a grand supply of such 
things as Melicerta, Stephanoceros, and several kinds of Floscules, 
Stentors, Hydra, both viridis and vulgaris, Amceba, innumerable 
infusoria and algze, and some new or rare Desmids, as noted by 
Mr. Wills, but has given me, in addition, a constant supply of such 
rarities as Qcistes umbella, Melicerta annulata and Ti wbicularia naias, 
with Tardigrada and free rotifers, etc., in abundance. In fact, I 
have only to complain of an embarras de richesses, and regret that 
want of time has prevented me doing as much with them as I could 
have wished. 
Though the construction of a pond, or what in this case may be 
better understood if called a fountain basin without the fountain, is 
a simple matter, yet I know from experience that it is by no means 
certain to be made successful at the first attempt. Mine is a brick 
structure of about eight feet outside diameter, and about two feet 
six inches in depth, measured from the top edge to the base ; the 
inside is made to slope at a good angle, which is very important. It 
stands about eighteen inches above the level of the surrounding 
ground, making nice sloping banks for about half its circumference, 
the inside being asphalted, which renders the whole perfectly water- 
tight. It has an outlet and a temporary means of supplying water, 
but the former is never required, and with the bountiful supply of 
