24 
with low than with high powers. Extreme nicety of preparation 
and elaborate illumination are not required with them, while the 
_ excellence of modern halfs and fifths is so great that appeals to 
higher powers are only occasionally needed. Whether we use 
high or low pewers, we should—in original investigations—be on 
our guard against the unconscious tendency of the mind to make 
‘‘the wish father to the thought ;” and, although we cannot be 
altogether free from preconceived ideas, their influence should be 
limited to the suggestion of enquiry. 
The structure of some of the diatom valves, which, although 
demonstrated nearly fifteen years ago, was, in consequence of the 
erroneous views of Griffiths, Wallich, and others, held still to be 
an open question, until only last year, the President of the Royal 
Microscopical Society announced his demonstration of their 
structure as a ‘‘ New birth to the Microscope.” 
Most conducive to a true knowledge of objects is their examin - 
ation in a recent state, and an acquaintance with the appearance of 
ordinary things will be found much more valuable than the settle- 
ment of a diatom or podura question. 
Our principal object, however, should be to enquire into the 
natural history of our own locality, the minute fauna of which 
has been but imperfectly examined. 
Our shore offers every inducement to extend research. The 
smaller crustaceans are scarcely known amongst us, although two 
of the most curious and interesting—the Caprella and Ammoihea 
—abound on the weed at Kemp Town and give promise of allied 
species of greater rarities as a reward for search. Acorn barnacles 
and shore crabs are instances of strange metamorphosis, as are also 
the polyps, of which laomedu obliqua and geniculata abound. The 
urn-shaped egg cases of purpura lapillis and the ribband-like strap 
of eggs of doris tuberculata can generally be found to illustrate the 
extraordinary embryonic development of the mollusca ; there is, 
in fact, scarcely a limit to the list of subjects waiting for examin- 
ation. 
For a full appreciation of minute structure comparison with 
permanent specimens is both necessary and interesting, They 
cannot, however, be seen under sufficiently varied conditions, and 
we may as well take an ancient Egyptian as a specimen man as 
