The animals upon which the experiments were tried were 
the rotifers (rotifer vulgaris). 
A certain amount of air was washed with distilled water 
and life allowed to originate in the solution, so that it could 
he seen at once what influence the amount of acid usualty 
found in air had upon the life. 
As a rule it required five days to bring the rotifers to 
perfection. The method of experiment was very simple. 
After animal life had been procured in the solution a 
known amount of the various acids used was then added, and 
allowed to stand one day, this was repeated till enough bad 
been added to destroy life. 
The results of these experiments are embodied in the 
following tables : — 
TABLE I. 
SULPHURIC ACID ADDED. 
Time allowed 
to stand. 
Days. 
Total Acidity. 
Grins, per Litre. 
Remarks. 
5 
0'065 
Animal life very abundant. Rotifers 
in very active condition. 
6 
‘ 0-084 
No perceptible difference in appear- 
ance of life. 
7 
0-097 
Brownish shade evident in water. 
Want of clearness in portion ex- 1 
amined. Small ‘clots’ of vegetable 
matter visible. Rotifers languid, 
seemingly disinclined to move. 
8 
0-153 
Life continued for about an hour, 
all traces then disappeared. The 
water presented the appearance of 
being filled with decomposing and 
decaying organic matter, which 
was floating about in ‘shreds.’ 
