THE NERVE SPIRIT. 51 



the identification of life with bricks and mortar would still stand. 

 In this case the truth, or the living multitudes, though seen, would 

 lend itself to the fallacy ; the only escape from which would be by 

 analogy, proclaiming that solid houses everywhere are dead, though 

 inhabited by fluid or freely movable living beings ; by imagination 

 or hypothesis, guessing that towns and streets are for men, and not 

 vice versa ; and by reason or theory, affirming mankind, and account- 

 ing for the appearances of the city upon the wants of its substantial, 

 though separately invisible inhabitants. 



But IV. the existence of an animal spirit has great historical pro- 

 bability attached to it. For the course of knowledge has consisted, 

 not in confirming abstractions, but in merging them in some ade- 

 quate reality, such as we are now claiming for the life and spirit of 

 the brain. The concrete form of things, or the tracing them home, 

 is the final victory of knowledge touching mere existence. So long 

 as life is an indeterminate phrase, applied without distinction to the 

 whole system, the study of that life has not commenced, for its 

 presence has not been gained; but when its proper currents are 

 found, and the mind traverses them, then the separate knowledge of 

 their properties can begin, but not sooner. And, moreover, the 

 triumphs of this age are peculiarly due to the introduction of the 

 mind to the empire of the fluids. The steam engine and its nervous 

 spirit, steam ; the railway and its locomotive fluid, the train ; the 

 wire and its electric spirit, show the practical benefits of the subor- 

 dination of the solid to the fluid. And in human progress, it is the 

 fluid and the modifiable that give motion and impulse to the other- 

 wise fixed. What are quickness, conception and imagination, but 

 the fluids of the mind : regard them at work, and you can bring 

 them under no other analogy. They stir the old, hard world, and 

 permeate all things, and like nervous fluids are present in a moment 

 where their mission is, with the power of arranging and quickening 

 virtue that they have received in the fountains of thought. Indeed, 

 I see not that there is any known sphere of things, whose analogies 

 do not cry aloud for the existence of a fluid brain governing the 

 solid, and like it, organized, though on a more living plan. Thus 

 until a nerve-spirit be admitted, How can the science of the brain 

 be in fraternity with the other arts and sciences? 



