THE FIRST DEVELOPMENT OF ORGANIC LIFE. 7 



With regard to the latter, we first obtained clear ideas from 

 the natural philosophical researches and computations of 

 the great critical philosopher, Immanuel Kant, and on this 

 point I must refer the reader to Kant's " AUgemeine Natur- 

 geschichte und Theorie des Himmels " and to the numerous 

 Cosmogenies which treat the subject in a popular style. 

 We cannot here dwell upon questions of this kind. 



The organic history of the earth could begin only when 

 water in fluid drops existed upon its surface. For the very 

 existence of all organisms, without any exception, depends 

 on water in the fluid state, their bodies containing a con- 

 siderable amount of the same. Our own body, in its fully 

 developed state, contains in its tissues 70 per cent, of water 

 and only 30 per cent, of solid matter. The 'amount of water 

 is still greater in the body of the child, and is greatest of all 

 in the embryo. In early stages of development the human 

 embryo contains more than 90 per cent, of water, and not 

 10 per cent, of solid matter. In low marine animals, 

 especially in the Medusae, the body contains even more than 

 S9 per cent, of water, and not even one per cent, of solid 

 matter. No organism can exist and perform its vital 

 functions without water. Without water there is no life. 



Water in the fluid state, which is, therefore, in- 

 dispensable for the existence of life, could not, however, 

 appear upon the earth until after the temperature of the 

 surface of the fiery globe had sunk to a certain point. 

 Before this it existed only in the form of steam. As 

 soon, however, as the first drop of water in a fluid state was 

 precipitated by cooling from the envelope of steam, it began 

 its geological action, and from that time to this it has 

 effected continual changes in the modification of the hard 



