Pasteur on Spontaneous Generation. Ps) 
0 confute various objections made by advocates of spontane:- 
_ ous generation, Pasteur undertook to determine the relative 
abundance of organic germs in different localities. A series of 
flasks were all one-third filled with the same putrescible fluid (a 
solution of sugar and albumen was employed in most of the ex- 
eriments). The fluid was then boiled for 2 or 8 minutes in the 
asks and the neck of each flask was drawn out to a fine point 
and hermetically sealed while the fluid was hot. These flasks 
were then taken to different localities and the points of the necks 
were broken and the air of the several localities allowed to rush 
in and fill the flasks, This violent ingress of air carried in of 
course all the dust held in suspension and all other principles 
known or unknown associated with it. In this condition each 
flask was again hermetically sealed and the whole placed where 
a 
of animalcules and mucors. The results of these experiments 
enerally in 3 or 4 days the liquid in the flasks was found 
altered, but in flasks placed in identical conditions were found 
very different organisms—much more varied so far as mucedines 
d 
exposed to ordinary air. On the other hand it frequently hap- 
pened in a series of experiments that several of the flasks re- 
mainéd absolutely unaffected for an indefinite me as if it had 
received only calcined air. 
This simple and unobjectionable method of experimenting 
appears to demonstrate that the cause of so-called spontaneous 
