SCIENCE AND RELIGION 219 



may seem almost impious to probe into the constitution of 

 living matter, let me reassure them. In the old days it was 

 accounted to Galileo as an offence against religion that he should 

 demonstrate that the earth was not the centre of the universe ; 

 that the sun did not travel round it, but it round the sun. We 

 all now accept Galileo's teaching, and our religion is in no whit 

 weakened thereby. Less than a century ago our forefathers 

 regarded as heretics those geologists who taught that fossils 

 were the remains of living beings, and that therefore the earth's 

 age, instead of being an odd six thousand years, as Archbishop 

 Ussher and others had computed, must be some hundreds of 

 thousands of years, if not millions. Every one nowadays 

 accepts the geologist's evidence without thereby being accounted 

 an enemy of revealed religion. Fear not, therefore. True 

 religion is unaffected by results of research upon natural 

 phenomena. 



So now to come to my subject — What is life ? In the first 

 place, if we analyse living matter, or, more accurately, matter 

 that has been endowed with life, whether we take the most minute 

 vegetable or the largest animal, from the simplest to the most 

 complex, we gain one particular order of substances as the result 

 of our analysis, an order only found in nature in connexion 

 with matter that has been living, and these substances we 

 speak of as proteids, or proteins. Save for water and 

 certain very simple salts of sodium and potassium, these 

 proteins are the only bodies common to all forms of matter 

 that have been endowed with life. There are plenty of other 

 substances which we may gain from certain orders of living 

 matter — chlorophyll, starches, fats, and so on — but these are not 

 universally distributed. The proteins are the one order of 

 substances derivable from all animate bodies. We may express 

 this in another way by saying that life is immediately associated 

 with the presence of proteins. This, however, is not absolutely 

 correct ; we are not convinced that the proteins as such are 

 actually present in living matter — in fact, when we isolate these 

 proteins they do not exhibit the properties which we associate 

 with life : they cannot move, they cannot grow, they are in- 

 sensitive to stimuli. We only know that dead organic matter 

 yields proteins. It is more correct to say that life is associated 

 with the presence of proteidogenous matter — of matter which 



