310 THE MICROSCOPICAL NEWS. 
doing us grievous bodily harm, and the young microscopist ofteh 
thinks that all he has to do is to place a few drops of such water 
upon a glass slide, and look at it under the Microscope, when all 
the forms imaginable will present themselves. No greater mistake 
could be made—organisms are present to a greater or less extent 
in all water supplies, but the water from service pipes, as a rule, 
contain so few of them that some special method of operation and 
examination is necessary on the part of the microscopist. 
Some year or so ago we were very much amused at seeing a 
report of the London water supply containing the statement that 
this water contained “moving organisms.” We do not know 
whether this was intended as a discovery. If so it is probable 
that a more careful search would have discovered them at a much 
earlier date. 
In America the use of the Microscope is better known in con- 
nection with water analysis than it is with us, and it would be well 
if some of our chemists would abandon their inaccurate methods 
of chemical analysis, and call in the Microscope to their aid. 
There zs something to be seen in water if the operation of 
“seeing” is gone about in the right way, and as an instance of 
this we give illustrations of the residues of two samples of water 
used for drinking purposes. 
Antmal.and Vegetable Prégiotionin 
Fig. 71. Fig. 72. 
Small entomostraca, diatoms, and small rotifers abound in this 
residue, and it may be as well to state that a drop of the water, if 
placed simply on the glass slip, and examined under the Micro- 
scope, would most probably show nothing at all. The fact is that 
the organisms are so few in number, and diffused through such a 
large volume of water, that they must be concentrated ere they 
can be detected, and this may be done in the following manner :— 
Professor Romyn Hitchcock, the able editor of the American 
Monthly Microscopical Journal, in 1881, gave instructions to his 
correspondents as follows :—‘‘ The Editor would consider it a 
great favour if correspondents in different cities would send him 
filterings from their water supplies, from time to time, for com- 
