I50 THE EVOLUTION OF MAN. 



same principles as a civilized state, in which the several 

 citizens have devoted themselves to various services directed 

 towards common ends. This comparison is of the greatest 

 service in enabling us thoroughly to understand the con- 

 struction of Man from many cells of various kinds, and to 

 understand also the harmonious co-operation of these 

 various cells for an apparently pre-conceived purpose. If 

 we bear this comparison in mind, and apply this significant 

 idea of the developed many-celled organism as a civil union 

 of many individuals, to the history of the evolution of this 

 organism, we shall obtain a correct view of the real nature 

 of the first and most important processes of evolution. We 

 can even, on deeper reflection, guess the first stages of 

 development, and establish them a priori, before we call 

 observation, a posteriori knowledge, to our aid. 



For once we will reverse the process, and will not, as 

 will be the case hereafter, first observe the facts of Ontogeny 

 and then attach their phylogenetical significance to them. 

 Beginning at the' other end, let us here try to guess the 

 course which evolution must have taken, if the comparison 

 is well founded. Then if, afterwards, the facts of Ontogeny 

 confirm our preconception, we shall be yet more firmly 

 convinced of the truth of our views on Phylogeny. This 

 agreement will afford us a more striking justification of our 

 views than can be gained in almost any other way. 



Let us therefore first answer this question : " Granting 

 the correctness of the fundamental law of Biogeny, how 

 would the original one-celled organism which founded the 

 first cell-state, and thus became the ancestor of the higher, 

 many celled animals, — how must that organism have acted 

 at the beginning of organic life on the earth, or at the 



