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POPULAR SCIENCE REVIEW. 
very scarce : statements which, we see hazarded in common 
compilations of natural history, and slavishly copied and re- 
copied upon no authority, and with no test of their truth, — 
that “ millions of animalcules inhabit every drop of water that 
we' drink;” that “ all the waters on the earth are absolutely 
swarming with life,” and the like, are gross exaggerations. I 
have often examined with care samples of water from different 
localities, and in particular that supplied to the inhabitants of 
London by the different water companies, and found scarcely 
a trace of microscopic life, — no Monads , no Euglence, no 
Infusoria of any kind, no Entornostraca, no Rotifera, with 
the exception of a solitary Synchceta, or two, perhaps, spinning 
round, or two or three Polyarthroe jumping hither and thither, 
in a whole tumblerful. Sometimes such water is a little more 
peopled than at others ; but its tenants are always, as a rule, 
few and remote. Like most popular fallacies, the notion I 
allude to -rests on a substratum of truth ; there are waters of 
which it would be strictly true to predicate such facts ; but 
they are stagnant collections, usually very limited in area, in 
which decaying organic matter, vegetable and animal, affords 
abundant nutriment, in consequence of which the increase of 
animalcules, both by generation and spontaneous division, goes 
on with almost inconceivable rapidity. 
To return, however, to our Synchcetce, the bright sparkling 
tenants of bright sparkling waters. They are comparatively 
of considerable size, several species being just discernible 
with the unassisted eye, — in other words, being above one- 
hundredth of an inch in length, — which, with a proportionate 
width, is about the limit of ordinary vision under favouring 
conditions. Their characteristic form is that of a boy’s peg-top, 
especially if you select a specimen of the article with which 
Tommy Scapegrace has been for a week or two pertinaciously 
“ digging ” at his fellows’ tops, by which means the iron peg 
has been driven further and further in, till only just the point 
projects : then you have the Synchceta exactly, the projecting 
point representing- the minute foot with its tiny toes, which 
are commonly pressed together so as to look single. Now and 
then the animal rests on these united toe-tips, and rotates for 
several minutes, as if to maintain its character as a spinning- 
top ; then away it shoots, and g'lides swiftly and giddily through 
the clear water by the hour together without repose ; its enor- 
mous ciliary apparatus giving it great power of motion. The 
rounded front appears to be beset with cilia, but it forms a 
sort of indented crest or forehead, on which two antennae are 
seated, as well as some pairs of curious stout branched bristles — 
whence the generic name, from avv (sun), together, and yxurrj 
(chaite), a bristle — and which then descends on each side in 
