64 



ETERNITY OF LIFE 



of the test tubes. The experiments of P. Becquerel*^ were 

 technically sounder. He dried the spores of moulds, bacteria 

 and other micro-organisms and collected them on a glass slide 

 which was placed in a wide test tube. This was then hermeti- 

 cally sealed at the top by a plate of quartz, and then evacu- 

 ated and plunged into a vessel containing liquid air. The 



100 



90 



80 



,— 70 



t 60 

 vt 



z 

 u 



I- 



? 50 



111 



> 



u 



40 



30 



20 



10 



0.2 



04 



06 



0.8 



1.0 



1.8 



2.0 



2 2 



2.4 



2.6 



1.2 1.4 1.6 



WAVE LENGTH, /Z 



(i/i = 10,000 A = 00001 cm.) 



Fig. 4. Solar spectrum curves on top of the atmosphere. 



By permission from Radiation Biology, vol. ii by 



A. HoUaender. Copyright 1955, McGraw-Hill Book 



Company, Inc. 



spores were then irradiated with a mercury lamp through 

 the quartz plate. They were all destroyed after fairly short 

 periods of exposure. 



The supporters of panspermia brought forward numerous 

 objections to these experiments. It was suggested that there 

 are forms of bacteria which are specially resistant to ultra- 

 violet light ; that the bactericidal effect of the ultraviolet light 

 is due to oxidative or other chemical changes so that it can 



