Sentence:  Hereby , the external object viewed by the eyes remains the thing that is seen , not the retinal image , the purpose of which would be to achieve perceptive cooperation by stirring sympathetic impulses in the other sensory centers , <WSD>motor</WSD> tensions , associated word symbols , and consciousness . 
Meaning of the word marked with <WSD> tags:  machine that converts other forms of energy into mechanical energy and so imparts motion