ON THE CELL 307 



or means whereby the prolificating, and accumulating, 

 cell bodies, can be maintained in organic union, sufficiently 

 binding, or intimate, for the accomplishment of communal, 

 or organic, purposes. This advancing stage may be 

 described as, one of agglutination , by cellular contiguity, 

 and continuity, sufficiently intimate for purposes of con- 

 certed vital action, but devoid of a fully elaborated vital 

 energy conveying machinery, such as is provided in the 

 later stages of embryonic development. 



The yet more advanced stage of embryonic develop- 

 ment, which consists in the arrangement, of the now 

 rapidly increasing primitive cells, into layers of dif- 

 ferent, character, and position, where the blastoderm 

 is divided into the ectoderm, the mesoderm, and the 

 hypoderm, necessitates the laying down of the foundation 

 of the future nervine organisation, by super-position, inter- 

 position, inter-penetration, and co-ordination, of structure, 

 for the production, conservation, and circulation, of 

 energy, and non-plastic, and colloidal, nutritive materials, 

 which now becomes, more and more, required, by the 

 provision of a system of intercellular nervine circula- 

 tion, of vital energy and plasma ; this stage coincides with 

 the provision of a system of inter-cellular communicating 

 processes, or " linking up " cellular structural arrange- 

 ments, which becomes the basis of the future sympathetic 

 nervous system. All these phases, or stages, in the 

 evolution of the details of cellular development, and 

 perpetuation, with the involved problems of vital energy 

 production, and distribution, and plasma circulation, 

 belong to, and are concerned alike in, the origin, and 

 succession, both of vegetable, and animal, forms, a line 

 of demarcation becoming noticeable, at the next stage, 

 or where the conditions of life become more complex, 

 when, besides the sympathetic nervous system, which is 

 still utilised to conduct the organic work, or pure vitalism, 

 of the organism, a systemic nervous system is added, or 

 evolved, in the more advanced, or highly organised, animal 

 forms, in order to fit them for taking part voluntarily, 

 and intelligently, in the many processes embraced in the 

 " battle of life," on the movable, and constantly altering, 

 stage, of animal contention, and " struggle for existence." 



