42 THE ORIGIN OF LIFE 



would give positive results in about the same time 

 as the other solutions did that were made with 

 sodium silicate obtained from Martindale in 1906; 

 that is, in four to six weeks for the colourless, 

 and three to four months for the yellow solutions. 1 

 The results of all these comparative trials have 

 led to some other important conclusions. I have 

 found, for instance, that, whatever sample of so- 

 dium silicate has been used, organisms were ulti- 

 mately to be discovered in the solutions. Some 

 specimens, however, yield them much more quickly 

 than others. I have also, as a result of examin- 

 ing solutions in which only a minimum amount 

 of deposit was present, come to the conclusion that 

 in the previous series of experiments the difficulty 

 of finding the organisms has been needlessly great 

 owing to much more sodium silicate than was 

 necessary having been used in the composition of 

 the solutions and the consequent throwing down 

 of a large amount of deposit, from amid which 

 the organisms had to be discovered, although they 



1 This sample of sodium silicate has a specific gravity of 

 1.44, though it is always used by me diluted with an equal bulk 

 of distilled water. A tin containing some of the silicate of this 

 make has been reserved by Messrs. Allen and Hanbury at 6 

 Vere Street, Oxford Street, at my request, in case others may 

 wish to obtain some of the same sample for a repetition of the 

 experiments. 



