44 Vitality and Organization of Protoplasm. 



Inferences regarding phylctic agencies are, hoAvever, apt to stray more 

 or less Avidel}' from what has really occurred. To ayoid false expecta- 

 tions and wasted lahor it is well not to forget that the organic indiyidual, 

 together with its environment, are conjointly revealed to our perception 

 chiefly in the symbolical medium of our visual space. We perceive thus 

 definite forms representing on the one hand the organism, and on the 

 other its environment. And from direct or compared changes in our 

 field of vision we conclude that the changes in the organism have been 

 induced by corresponding changes in the environment. We distinguish 

 hereby, by dint of established experience, l^etween chemical composition 

 and activity, and purely physical or mechanical composition and activity. 

 And in the case of the organism and its environment, we rightly con- 

 clude that the observed changes wrought in the organism are chemical 

 changes induced during cetodermic activity by interaction with the 

 physical incitements emanating from the environment. But we know 

 as little the intimate nature of what in our perception appears as chemi- 

 cal substance, as we know by what means physical agents are empowered 

 to induce changes in the constitution of bodies. We symbolically per- 

 ceive the results without being able to form adequate conceptions of the 

 real nature of the activities, or of the actuating agents at work. Though 

 we know for certain that the living substance has, and steadfastly main- 

 tains, a most specific chemical constitution, we are explaining its vital 

 phenomena only symbolically, principally in terms of visual perception. 

 The adaptation of the structures of the 'organism to the functions, 

 which they exercise in relation to external conditions, consists evidently 

 in the chemical elalwration of the living substance into functionally 

 adapted structures, which are perceived as out and out organized forms. 



Assimilation is the consummation of the nutritive process. And the 

 vitality of the substance composing living beings, with all its principal 

 manifestations, such as irritability, motility, growth, regeneration and 

 ontogenetic evolution, must all remain enigmatical, so long as the true 

 nature of the assimilative process is not understood. The transforma- 

 tion of lifeless into living substance underlies all vital function. And 

 this conversion of lifeless into living substance consists, as has been 

 showTi, simply in complemental assimilation of nutritive material, by 

 means of which the living substance is reintegrated, after it has suffered 

 disintegration. It does not consist, as generally accepted, in the new- 

 formation of vital units. The restitutive process, actuated by the in- 

 trinsic affinity and avidity of functionally deteriorated protoplasm 

 towards nutritively complemental material, renders alone possible the 

 vital reaction, the motility, tlie growth, the regeneration, and the repro- 

 duction of organic beings, togctl:er with the maintenance of their struc- 

 tural and functional identity. 



Such sweeping generalizing from the vital phenomena of beings low 

 in the scale of organic evolution to the vital phenomena of organisms 

 in general, may appear overbold and unjustified to many, perhaps to 

 most investigators. But we are dealing here with Ihe observal)le ]u-ocesses 



