FERMENTATION 31 



infection. So early as March, 1863, when he was 

 presented by J. B. Dumas to Napoleon III., he 

 told the Emperor that his one ambition was to get 

 to know the causes of putrid and contagious 

 diseases. So early as 1862, he published a note on 

 the presence of certain germs in ammoniacal urine, 

 such as are present in disease of the bladder. So 

 early as November, 1860, writing of his experiments 

 at Chamonix on the sterility of air above the snow- 

 level, " What is wanted," he said, " is to extend 

 these observations far enough to prepare the way 

 for a thorough study of the origin of different 

 diseases.'* 



We are so full, nowadays, of germ-facts, that we 

 have left off talking of " the germ-theory." It is 

 just half a century, since he demonstrated his 

 method to all Paris : we must put ourselves back 

 fifty years, to 1864. We must note the one thought 

 which dominated the germ-theory. It was the 

 thought of putrefaction. Broth, infected by the 

 living dust of the air, goes bad, stinks, becomes 

 putrid. The germs which have got into it are the 

 germs of putrefaction. Do away with these germs, 

 keep them out or kill them off, and you will pre- 

 vent putrefaction. That was the teaching of the 

 germ-theory, in 1864. Then, in 1865, came Lister's 

 first use of carbolic acid to prevent putrefaction in 

 a case of compound fracture. 



