THE BEGINNINGS OF LIFE. 



tains any notable quantity of living Bacteria^ or of their 

 germs, whether visible or invisible. I have always 

 found that a simple solution of ammonic tartrate, 

 which has been placed — without previous boiling — in 

 a corked bottle of greater capacity, will become turbid 

 in two or three days, owing to the presence of myriads 

 oi Bacteria I whilst a similar solution, previously boiled, 

 may remain for ten days, three weeks, or more, without 

 showing the least trace of turbidity, although the open 

 neck of the bottle or flask in which it is contained may 

 be covered only by a loose cap of paper. And yet, 

 at any time_, in order to make this fluid become turbid 

 in twenty-four to forty-eight hours, all that one has 

 to do is to bring it into contact with a small glass 

 rod which has just been dipped into a solution con- 

 taining living Bacteria ^ 



If we find that an eminently inoculable fluid will 

 remain for two or three weeks, or perhaps more, in 

 contact with the air without becoming turbid, though 

 it will always become turbid in two or three days if 

 brought into contact with living Bacteria^ what can we 

 conclude, but that living Bacteria are not very common 

 in the atmosphere ? These most striking facts can be 

 easily verified by other observers ^. 



On this subject also, I am glad to find that my 



1 The solution during the whole time being exposed to a temperature 

 of 75° to 85° F. 



2 Somewhat similar facts were indeed first recorded by Prof. Cantoni, 

 ' Rendiconti di Lombardo,' Nov. 25, 1869. 



