194 ORIGIN AND NATURE OF LIFE 



in distilled water, and (b) sodium silicate 

 and per-nitrate of iron, also in distilled water. 

 The latter solution gave more abundant 

 organisms according to the author. The 

 exact concentrations used may be found in 

 his work as quoted in the bibliography at 

 the end of the volume. 



No results are said to be obtained in a short 

 interval such as one or two weeks, and this 

 is used as evidence to prove that the results 

 found in other tubes kept longer are genuine 

 and not fortuitous from occasional infection. 

 The proofs relied upon by Bastian in favour 

 of the products he obtains being really living 

 organisms, are (1) the microscopic appearances, 

 (2) the staining properties to micro-chemical 

 reagents, and (3) the fact that, when the 

 structures are sown into proper nutrient 

 materials, then they reproduce themselves 

 just as micro-organisms would reproduce 

 themselves when sown into a nutrient medium. 

 Bastian draws a careful and quite legitimate 

 distinction between a nutrient medium con- 

 taining material capable of nourishing and 

 causing to multiply a micro-organism already 

 there, and a medium capable of causing 

 organisms to engender. 



An important point is that Bastian found 

 that generation occurred better and the 



