loo THE ORIGIN OF LIFE 



this is merely analogy, and we must remember, as 

 the great Darwin has well said, " analogy is a 

 deceitful guide," still, if that analogy has pre- 

 scribed or suggested results which have since been 

 verified, its utility should have a claim to our 

 attention before it is explained. 



The first experiments were repeated with radium 

 bromide. A minute quantity of the salt con- 

 tained in a small glass tube, one end of which 

 was drawn out to a fine point, was introduced into 

 an ordinary test-tube containing bouillon. The 

 test-tube was plugged with cotton wool in the usual 

 way with such experiments, and then sterilised at 

 a temperature of 130° C. for about thirty minutes 

 at a time. On cooling, as soon as the liquid had 

 coagulated, the fine end of the inner tube containing 

 the radium was broken by means of a wire hook 

 in a side tube. The salt was thus allowed to 

 drop on the surface of the gelatin. After twenty- 

 four hours signs of growth were already visible ; 

 and on opening the tube and examining the culture 

 microscopically the results were as those previously 

 obtained. 



Their appearance is indeed most striking. It 

 is curious, however, that with bromide the cultures, 

 although produced more rapidly, did not spread far 

 into the interior of the gelatin, as did those due to 

 the chloride, but the cultures after six weeks or so 

 were even more remarkable and resembled the cultures 

 of tuberculosis. 



Slides were made in the usual way. The appear- 

 ance was that shown in Plate I. It is noteworthy 



