


EXPERIMENTS WITH SALINE SOLUTIONS 231 
known that distilled water after it has stood for some 
time in ordinary vessels may be found to contain 
simple micro-organisms—growing more especially 
on the lower surface of the containing vessel. By 
using recently distilled water, however, we can 
almost get rid of all organisms—and certainly can 
get rid of spore-bearing Bacilli. So that the few 
micro-organisms that may chance to be present 
would not be of a kind in any way likely to com- 
plicate our results. If the thermophilic Bacteria are 
absent, as we are told, from ordinary tap-water,! 
they are still less likely, as all must admit, to be 
found in freshly distilled water. And, even in regard 
to the relative purity of ordinary tap-water, the 
following facts should be borne in mind. MM. 
Pasteur and Joubert made an extensive series of 
investigations concerning the “germs of lower 
organisms” that were to be found in the waters 
of different regions, and among them in the water 
of the Seine (certainly very much fouler than any 
ordinary tap-water would be), and yet all they 
could say as to the capacity of resisting moist heat 
possessed by the organisms or germs found to be 
existing therein was this :?— 
‘““A drop of the water taken from above Paris, and still more 
when taken from below, is always fertile, and gives rise to the 
development of several kinds of Bacteria, among which there are 
some whose germs resist more than 100° C., when in the moist 
state and in media which have not an acid reaction.” 
Subsequently to the date of these investigations, 
1 See p. 69. 2 Compt. Rend., January 29, 1877, p. 208. 
