ff PHYSICAL EXPRESSION. 



analogies from the processes proven in plants to 

 processes seen in higher organisms. If physical 

 forces have played a large part in bringing about 

 evolution, we should surely study the processes in 

 simple organisms. If light and gravity are proven 

 to cause certain phenomena in plants, and if we 

 see similar phenomena in men, why should we 

 assume those phenomena in man not to be due to 

 light and gravity, but to be due to "mind," or 

 " feeling," or " consciousness," which we cannot by 

 any scientific process directly deal with ? 



It has often struck me that recent biological 

 inquirers^ in the just desire to study only what 

 is capable of physical investigation, have ex- 

 amined material structures rather to the neglect of 

 equally materialistic forces displayed in the 

 matter, and that motion which has been so care- 

 fully and satisfactorily studied by the physical 

 experimentalist * has not been sufficiently studied 

 by the physiologist. I think that movement in 

 living beings is capable and worthy of detailed 

 study. Following on these lines of thought, this 

 work has been written, showing how largely the 

 expression of vital functions may be described in 

 terms of movement and movement is capable of 

 physical investigation. 



In observing living organisms there are two 

 principal methods that may be employed. (1) 

 Observation of the body,f or corporeal, material 

 structure of the subject : this may be a histological 



* The works of Grove and Tyndall. 



t See specially chap. xvi. as to proportional development. 



