340 
nothing was added to it. The glasses were then carefully 
plugged with cotton wool. On Jan. 
12, glass @ was quite milky in ap- 
pearance, and had a gelatinous scum 
on the surface. It contained myriads 
of bacteria and a few torula cells. 
Glasses b and c were also turbid, 
the former more than the latter. 
The microscopical appearances were 
the same in all. In d no change 
could be detected either by the 
naked eye or with the microscope. 
Some of the liquid which remained 
in a glass exposed to the air was 
covered with tufts of penicil- 
lium. 
In this experiment, which was 
confirmatory of the preceding, it is 
worthy of note that the two waters 
used to impregnate the test solution 
the most decided effects were produced by the distilled water. 
XVI—January 17.—Pasteur’s solution was made with 
ordinary distilled water. A sufficient quantity was then 
boiled, and immediately distributed in four eprouvettes, all 
of which had been heated immediately before to a tempera- 
ture of 200° C., the quantity of liquid in each being about 
equal. The conditions of experiment were as follows :—l. 
The liquid was allowed to cool, and then three drops of 
freshly distilled water were added to it with the aid of a 
small pipette which had just been heated in the flame of a 
Bunsen’s burner. This water was collected in a superheated 
glass from the glass distilling apparatus, which had been 
previously thoroughly steamed out. 2. The same, excepting 
that three drops of ordinary distilled water were used. 3. 
Three drops of water from the tap were added. To a fourth 
eprouvette no addition was made. ; 
On January 24 the liquids in 1 and 4 were perfectly limpid, 
and showed no trace of organic forms ; 2 and 3 were milky, 
especially the former. Both contained bacteria. Up to the 
present time the eprouvettes 1 and 4 remain perfectly barren. 
This experiment shows that if due precautions are taken, 
distilled water may be obtained in such complete purity that 
it is free from germinal particles, whether of microzymes or 
fungi; and that the zymotic power (if I may be permitted to 
use this term to express the faculty to determine the develop- 
ment of organic forms in a test solution to which it is added) 
2 
After standing a week 
with which distilled water is mixed, has 
lugged with cotton wool and charged with test liquid 
to which distilled water has been added in the prescribed 
so as to avoid mixin 
P 
1e upper layer, 
It is 
proportion, 
become turbid. 
Fic. 2. Eprouvette used in this and the following experiments. 
th 
