228 THE ORIGIN OF LIFE 



and doubtless the most stable ones wbich constitute 

 protoplasm, are also the ones which are to be found 

 in the largest quantity. This points to the fact 

 that protoplasm is of very ancient origin and must 

 have been formed of at any rate that substance of 

 which it is but the direct descendant ; as radium is 

 the descendant of uranium and probably of less 

 stable elements, the ancestors of protoplasm must 

 have been formed at a very early date in the 

 history of the earth. 



Cellular protoplasm, however, is doubtless of 

 much later origin because the cells are destroyed 

 by heat ; nevertheless, it seems highly probable 

 that the lightest elements of each group, such as 

 carbon, nitrogen, oxygen, and hydrogen, are the 

 products of disintegration of other highly unstable 

 elements not yet discovered, as also iron, phosphorus, 

 sulphur, and helium. In fact, helium we know 

 is the final product of disintegration of radium. 

 Those heavier elements do not necessarily, in their 

 transformation downwards, have to pass for any 

 length of time through each of the intermediate 

 stages ; they are most probably transformed into 

 their more stable groups almost directly. The con- 

 stituents of biogen, therefore, would seem to be, 

 from our reflections on the subject, the unstable 

 ancestors of these more permanent elements. 

 Biogen, therefore, is once more either an element 

 or a combination of elements in a highly unstable 

 state and capable of giving rise to extremely 

 complex organisations. 



Many ingenious speculations may be framed on the 



