THE PRESIDENT'S ADDRESS. 273 



should not expect to be able to observe spontaneous generation 

 in infusions of organic matter, but should conduct our experiments 

 with purely inorganic substances. 



Dr. Bastian's a priori position is a very strong one. If 

 spontaneous generation took place once upon the earth's surface- 

 there is no known reason why it should not take place to-day, 

 while the actual existence of countless hosts of extremely 

 primitive organisms alongside the most highly finished products 

 of organic evolution certainly seems to support the view that such 

 primitive forms are constantly arising from inorganic constitu- 

 ents and emerging from the obscurity of their birth only when 

 they have reached a stage of evolution at which they are capable 

 of appealing directly or indirectly to the human senses. 



Dr. Bastian employed for some of his recent experiments* a 

 very dilute solution of sodium silicate, to which was added either 

 a minute quantity of pernitrate of iron, or a small quantity of 

 phosphoric acid and ammonium phosphate. He joints out r 

 however, that the sodium silicate is a variable commercial product 

 and attributes to this fact certain otherwise unaccountable 

 variations in the results obtained. The experiments were there- 

 fore repeated with pure colloidal silica in place of the sodium 

 silicate, and positive results were again secured. 



The method of procedure is as follows. The solution to be 

 experimented upon is hermetically sealed up in a glass tube 

 and heated to about 130 C. for ten minutes or more. After the 

 lapse of a few weeks, or in some cases months, during which time 

 the sealed tubes have been exposed to ordinary atmospheric 

 conditions, they are found to contain living organisms, Torulae y 

 Bacteria and even moulds being present in varying quantities. 

 Dr. Bastian claims that these organisms have arisen in the 

 tubes by spontaneous generation, or, as he terms it, Archebiosis. 

 He supposes that the living matter probably originated in 

 the first place in the form of ultra-microscopic particles, but 

 maintains that in the course of a few weeks or months these 

 particles developed into the organisms finally found. 



To a certain extent these results are, as I have already pointed 

 out, in accord with purely a ])riori expectations, but in other 

 respects they appear improbable to the last degree. Most of the 



* For a full account of these experiments the reader is referred to 

 Dr. Bastian's recent book on The Origin of Life. 2nd Edition, 1913. 



