Spirazines 7 



1/25,000 cm = 4,000 Angstrom units, and in that 

 region we come dangerously close to the details 

 of molecular structure. 



That the phenomenon of self-duplication must 

 be due, either wholly or partly, to specific chem- 

 ical processes is generally admitted, but there is 

 a prevailing opinion that the molecular structures 

 which are necessary for this purpose must be ex- 

 tremely complex. The failure of all previous 

 efforts to devise some type of molecular structure 

 which is capable of duplicating itself does not 

 prove, however, that the solution of the problem 

 must lie in the direction of extreme complexity. 

 The complex molecular structures which make up 

 the tissues of the higher plants and animals have 

 developed gradually in the course of evolution, 

 and the fact that they are necessary for the 

 proper physiological functioning of the particular 

 organisms in which they now occur does not prove 

 that they were also the original cause of the fun- 

 damental life processes in the more primitive 

 organisms from which these higher plants and 

 animals have developed. 



With the exception of certain plasmodia and 

 syncytia which have no definite cell-walls, the 

 bodies of all higher plants and animals consist of 

 aggregates of separate living cells, all of which 

 are formed according to the same general plan in 



