260 A. A. Hayes on the Cochituate Water. 
appeared, and the water which had no action on iron, assumed 
its ordinary action on this metal. The erustaceans increased in 
quantity and size, the Cyclopsand Daphnia became predominant, 
and the cotton filters were soon closed by their bodies. Atten- 
tion was now given to the mass collected on the filter, as had al- 
ready been done with the sponges, and some vegetable organ- 
isms, including Conferva. 
‘The fish-lie odor was mostly retained by the filter, which 
had not been the case in the earlier experiments, atid it became 
easy to separate from the gelatinous mass on the cotton, the oil, 
with the odor, or apart from it. As separated from the mass, the 
oil possessed a fugitive green color, at times, but the dried filters 
extracted by ether, afforded a yellow oil. The = variations in 
color were found to be due to the state of the matter on the 
filter, which, evidently of animal origin, decayed rapidly, and the 
oil and odor became merged in a body, much like ad:pocere. 
The water, which had been purified’ by means of animal ehar- 
coal, was free from taste aid odor ; its vapor did not tie odor, 
and ra hips 3 part of the organic matter had disa 
chief contaminating matter in this water was arrested 
fei a hint by even a coarse filter, and the experiments had 
been repeated so frequently as to leave little else for chemical 
trials, I placed in the hands of Dr. John Bacon, for microscopical 
examination, the substance, like that, from which the odorous oil 
had heen taker 
Bacon at once detected the source of the oil, the bodies of 
the Cyclops aud Daphnia, being in large part filled ‘with it,*—ten 
or fifteen globules, of different sizes, could be seen in a single 
orless oil, and not a few had oil of a blackish blue, shading to in- 
digo blue. 
This fact explains = S stab me of green and olive green 
etherial solutions, and it was found that the decomposing re- 
mains, were often red aad Veltowish brown—and in that case af- 
forded light yellow solutions. No other substance, but those 
named, was found among numerous collections, which could af- 
ford oil ; the connection between the chemical proofs, ‘and mi- 
eroscopical observations was most skillfully made by Dr. Bacon, 
in the way of extracting the oil, while the subject was in t 
field of the instrument. 
At this point of the research, a series of experiments was 0N- 
detain, which demonstrated that the fluid oil first obtained by 
charcoal, was really due to the presence of broken 
2 crustaceans, which had given free oil to the water. 
.. x Darter Daphne aril Ware ith cl eho er! 
