WATER, WATER ANALYSIS, AND THE MICROSCOPE, 311 
parison. They can be readily collected by attaching a bag of fine 
cloth to the faucet (tap), and running the water for an hour or so. 
A large bag about six inches deep is preferable to a small one, as 
the water then flows more freely. ‘The sediment should be washed 
into a conical glass, and allowed to settle.” 
Even before this, Professor W. G. Farlow issued a small 
brochure illustrated with two plates, entitled ““On some impurities 
of Drinking Water caused by vegetable growths,” which was quite 
sufficient to allay any anxiety engendered by reading the sensational 
articles often appearing in our papers respecting water supply. 
In 1881 the Boston (U.S.A.) water supply was made the 
subject of many complaints, a strong “cucumber” taste was 
developed in it, much correspondence taking place upon the sub- 
ject in the Boston papers. Professor Ira Remsen undertook to 
investigate the matter, and his report confirms what we have 
already said regarding the value of chemical analysis in the last 
chapter. Professor Ira Remsen writes :— “ Having failed by 
chemical means to determine whether the substance which causes 
the ‘cucumber taste’ is at the bottom of the pond or not, I now 
undertook a special examination.” Further on he states, ‘‘ There 
is evidently something at the bottom which, by contact with air, is 
capable of giving off an odour. An examination soon revealed 
the presence of green masses, varying in size from that of a pin 
head to that of a pea. These were present in considerable 
quantity, and in allowing the vessels containing the mud to stand 
quietly for a short time the green masses rose to the surface of the 
mud.” Further investigation showed this green substance to be 
algee of the Nostoc family, and the Nostocs are known to give off 
a disagreeable odour when decaying. This, however, was not the 
cause of the “cucumber taste.” Finally, an examination of the 
debris collected at one of the effluent sluices showed an accumu- 
lation of Spongilla fluviatilis, the fresh-water sponge, which, while 
living, has a very strong odour, intensified by death, and Professor 
Alpheus Hyatt reported “ that the odour of the sponge shown me 
by Professor Remsen is like that of the water strongly intensified.” 
This little episode shows the value of microscopical analysis, 
which is even more strongly exhibited by Professor Elwyn Waller’s 
report on the Croton Water of 1881. Dr. Torrey was called upon 
to report upon the odour of the Croton water as early as 1859, 
and there is little doubt but that the plants alluded to in his 
report were Celospheritum and Anabena. In Professor Waller’s 
report it is shown that more than sixty towns are occasionally 
troubled with the odour of the water supplied to them. 
Of course the water of a stagnant pond is always found literally 
teeming with organisms of all kinds, and the reservoirs of the water 
supply of our British cities afford the microscopist many a good 
