THE GENERAL CONDITIONS OF LIFE 301 



it come to the earth from other worlds ? and this question he 

 answers by the theory of cosmozoa. 



For the possibility that germs capable of life came from space 

 through the atmosphere to the earth's surface, without perishing 

 from the incandescent heat arising from the enormous friction, 

 Richter believes that he finds a support in the assertion of 

 observers that in many meteoric stones traces of coal and even 

 humus and petroleum-like substances occur. If these can come to 

 the earth without undergoing combustion it is possible that germs 

 capable of life also pass through the atmosphere without losing 

 their vital capacity. 



That organic germs can endure a long journey through space 

 from one heavenly body to another without water and food can- 

 not be doubted, if in apparently dead organisms, such as the 

 spores of micro-organisms, there be recognised substance actually 

 capable of life that can continue in its apparently dead condition 

 for a long time without water and food and yet revive as soon 

 as it comes under the required vital conditions. 



Independently of Richter, some years later Helmholtz and Sir 

 William Thompson discussed the question whether life may not, 

 perhaps, have been transferred from other heavenly bodies to the 

 earth ; and both termed this view not unscientific. Helmholtz 

 ('84) says : " Meteoric stones sometimes contain hydrocarbon 

 compounds ; the intrinsic light of the heads of comets shows a 

 spectrum that is very similar to that of the incandescent electric 

 light in gases containing hydrocarbons. But carbon is the 

 characteristic element of the organic compounds of which living- 

 bodies are composed. Who can say whether these bodies that 

 swarm everywhere through space do not spread also the germs of 

 life wherever a new world has become capable of affording a 

 dwelling-place to organic creatures ? And this life we might, 

 perhaps, have reason to regard as even allied to our own in germ, 

 however various may be the forms in which it might adapt itself 

 to the conditions of its new dwelling-place." That meteors can be 

 the bearers of such germs Helmholtz holds to be entirely possible, 

 since large meteoric stones in passing through the atmosphere of 

 the earth are greatly heated upon their surface only, while in their 

 interior they remain cool. Helmholtz says, further, regarding the 

 theory of cosmozoa : " I cannot contend against one who 

 would regard this hypothesis as highly or wholly improbable. 

 But it appears to me to be a wholly correct scientific procedure, 

 when all our endeavours to produce organisms out of lifeless 

 substance are thwarted, to question whether after all life has ever 

 arisen, whether it may not be even as old as matter, and whether 

 its germs, passed from one world to another, may not have 

 developed where they found favourable soil." " The true alterna- 

 tive is evident ; organic life has either begun to exist at some one 

 time, or has existed from eternity." 



