ORIGIN OF LOWEST ORGANISMS. 39 



tremity of the drawn-out neck of the flask, which is 

 permitted to remain open. I then allow the flask to 

 cool. But, singular fact and one well calculated to 

 astonish every one acquainted with the delicacy of the 

 experiments relating to what is called 'spontaneous 

 generation ' the liquid of this flask will remain inde- 

 finitely without alteration. The flask may be handled 

 without any fear, it may be transported from place to 

 place, allowed to experience all the seasonal variations 

 of temperature, and its liquid does not undergo the 

 slightest alteration, whilst it preserves its odour and its 

 taste." If, however, the neck of one of these flasks be 

 broken off close to the flask itself, then, according to 

 M. Pasteur, the previously unaltered fluid will, in a 

 day or two, undergo the ordinary changes, and swarm 

 with Bacteria and Mucedinece. 



" The great interest of this method is," M. Pasteur 

 adds, " that it completes, unanswerably, the proof that 

 the origin of life in infusions which have been raised 

 to the boiling point, is solely due to the solid particles* 

 which are suspended in the air." He believes that any 

 living things pre-existing in the fluid itself would be 

 destroyed by the high temperature to which it had been 

 raised ; and that those contained in the air of the flask 

 would also be destroyed, if not expelled, by the process 



* As expressed, the proposition may be an approximation to 

 the truth. M. Pasteur, however, really endeavours to lead his 

 readers to believe that the " solid particles " which are efficacious, 

 are, in all cases, living " germs." 



