UNICELLULAR HUMAN GERM. 147 



those of other Mammals. This fact can be demonstrated 

 at any moment under the microscope, and it is useless to 

 close our eyes to this " immoral " fact. It remains as 

 incontrovertible as the important conclusions which we 

 have linked with it. 



The very important bearing which the Cell Theory has 

 on the whole conception of organic nature is thus very 

 clearly seen. The " place of man in nature " is radically 

 explained by it. Without this theory, Man is an unin- 

 telligible puzzle. Philosophers, therefore, and certainly 

 psychologists, ought especially to acquaint themselves 

 thoroughly with the Cell Theory. The human mind can 

 only be really understood by means of this theory, and its 

 simplest form is illustrated in the Amoeba. 



The extant Amoebae and the kindred one-celled organ- 

 isms, Arcellae, Gregarinse, etc., are therefore of great 

 interest, because they show us the simple cell in a per- 

 manently independent form. The human organism and 

 that of other higher animals, on the contrary, is only one- 

 celled in its earliest, immature condition. As soon as the 

 egg-cell is fertilized, it multiplies by division and forms a 

 community, or colony of many social cells. These dif- 

 ferentiate themselves, and by their specialization, by various 

 modifications of these cells, the various tissues which com- 

 pose the various organs are developed. The developed 

 many-celled organisms of Man and of all higher animals 

 resembles, therefore, a social, civil community, the numerous 

 single individuals of which are, indeed, developed in various 

 ways, but were original ly only simple cells of one common 

 structure 



