SPONTANEOUS GENERATION 197 



Dr. Bastian, in his recent work already referred 

 to, a note on which appeared in the Proc. Roy. Soc, 

 1905, describes his observations on what he regards 

 as the development of certain ciliated infusoria 

 from the eggs of a rotifer. He looks upon such 

 development as an instance, a remarkable instance, 

 of heterogenesis. This extraordinary suggestion, 

 strange as it may seem at first sight, would not 

 be more amazing than that organic life in certain 

 media should have originated from mineral or 

 inorganic matter. He has found that under 

 various conditions the egg of a rotifer can divide 

 up into otostomata, into amoebae, and into flagellate 

 monads. All this is very interesting, but it has 

 been received with scepticism by the scientific 

 world, as original discoveries always have been 

 and ever should be. 



Dr. Bastian, objecting as he very rightly does on 

 some of the grounds we have given to Pasteur's 

 experiment, has adopted the course of filtering 

 instead of that of sterilising. This method is one 

 again which is open to similar objections, although 

 it has the advantage that it does lead to positive 

 results. Sterilising, if it did lead to positive 

 results, may still be open to the objection that 

 some germs totally different from those which have 

 been eliminated have survived. The method of 

 filtration does not give us that satisfaction, because 

 in this case germs of the same kind as the larger 

 ones that are eliminated may still get through. 

 It is by no means certain that the method of 

 filtration will eliminate even those forms of lif§ 



