328 The Theory of Genetic Modes 



strued under the law of cause and effect as formulated 

 in physics and chemistry. Yet they give no adequate 

 explanation of the remarkable behaviour of the organism 

 in regenerating its parts. The vitalists, on the other 

 hand, resort to a view of a highly mystical character, 

 holding that the organism does what it is its nature to 

 do, and that no light can be shed upon its behaviour by 

 the principles of physics and chemistry. An interesting 

 transition from one of these extremes to the other, in 

 the same author's views, is to be found in the writings 

 of Driesch, who works out a theory which attempts to 

 hold to the adequacy of the formulas of physics and 

 chemistry in his AnalytiscJie Theoiie^ — which, by the 

 way, outdoes all the metaphysicians for stretches of pure 

 metaphysics, — and then in later writings goes over 

 gradually, in the presence of the astonishing revelations 

 of research, to a frankly vitalistic view. The conclusions 

 arrived at by Morgan show a somewhat vacillating at- 

 tempt to do justice to both points of view, at the same 

 time that a guiding principle whereby they can be rec- 

 onciled is quite absent. He says : " The fundamental 

 question turns upon whether the development of a spe- 

 cific form is the outcome of one or more ' forces,' or 

 whether it is a phenomenon belonging to an entirely 

 different category from anything known to the chemist 

 and the physicist. If we state that it is the property 

 of each kind of living substance to assume under certain 

 conditions a more or less constant specific form, we 

 only restate the result without referring the process to 

 any better known group of phenomena. If we attempt 

 to go beyond this, and speculate as to the principles 

 involved, we have very little to guide us. We can, how- 



