24 THE SOUL. 



proper career of circulation. It is needless here to dwell on the manner 

 in which the most refined principles of hydraulics are brought into play, 

 or to speak of the manner in which forces of compression and elasticity 

 are introduced ; how that there are valves which open only in one way 

 to let the current pass, or how some of these, as in the like human con- 

 trivances, are tied down in their action by cords. Moreover, since it is 

 required that the animal shall go in search of its food, muscles of loco- 

 motion, which act upon purely mechanical principles on the bony skele- 

 ton, must be resorted to, and so the animal structure becomes a most 

 elaborate and complicated machine. 



In this regard the human body may be spoken of as a mere instrument 

 Physical as- or engine, which acts in accordance with the principles of me- 

 pectofman. c h an i ca l an d chemical philosophy, the bones being levers, the 

 blood-vessels hydraulic tubes, the soft parts generally the seats of oxida- 

 tion. But if we limit our view to such a description, it presents to us 

 man in a most incomplete and unworthy aspect. There animates this 

 machine a self-conscious and immortal principle the soul. 



Though in the most enlarged acceptation it would fall under the prov- 

 Thesoui- its * nce ^ P^7 s ^g7 to * reat of this immortal principle, and to 

 nature and re- consider its powers and responsibilities, these constitute a 

 ies ' subject at once so boundless and so important, that the phys- 

 iologist is constrained to surrender it to the psychologist and theologian, 

 and the more so since the proper and profitable treatment of it becomes 

 inseparably involved with things that lie outside of his domain. 



Yet under these circumstances, considering the ever-increasing control 

 which scientific truth exerts over the masses of men, considering too how 

 much the welfare of the human family depends on the precision and 

 soundness of its religious views, it is the duty of the physiologist, if for 

 the reasons that have been specified he yields this great subject to others, 

 to leave no ambiguity in the expression of the conclusion to which his 

 own science brings him. Especially is it for him, whenever the oppor- 

 tunity offers, to assert and to uphold the doctrine of the oneness, the im- 

 mortality, the accountability of the soul, and to enforce those paramount 

 truths with whatever evidence the structure of the body can furnish. 



For this reason, he can not recall but with regret the existing use of 

 many terms, such as mind, intellect, vital principle, spirit, which, though 

 they were at first doubtless employed as expressions of the function's or 

 qualities of the soul, have in the course of time gathered other meanings 

 and confused the popular ideas. They have brought about a condition 

 of things in science not unlike that which prevailed in theology during 

 the reign of polytheism. Constrained, perhaps, himself by the necessities 

 of language to use such phraseology, it is for him at the outset to leave 

 no doubt of the views he entertains, and, as far as he can, prevent such 



