182 THE HUMAN HEART. 



body, and especially into the blood. The red globules of the latter 

 are its most living parts, and may be likened to little caskets in 

 which this nervous fluid is carried about, and dispensed as life to 

 the tissues, to which it gives a natural, though engrafted capacity to 

 be acted upon by the brains and lungs, and to react on their own 

 account. The freeing of this nervous fluid in the capillaries is as a 

 millionfold torch that kindles the decompounded elements of the 

 globules, and produces a graduated scale of heats, of which the first 

 or living fire is the nervous fluid itself, instinct with its organic 

 emotion, and the excrement, residue or caput mortuum is the oxy- 

 gen and carbon which the blood and tissues yield to the curious 

 chemist; the difference between which two is greater than that be- 

 tween the smoking ashes of a burnt house and heaven's lightning. 



Were it not for this inspiration by the brain, the blood could not 

 be humanly alive, or in other words, the soul could not associate 

 with it. With respect to the change that takes place at the ends of 

 the arteries, or in the capillary circulation, where the blood loses its 

 arterial color, and purples or becomes venous, the manner of it is 

 sufficiently obscure, and has only been investigated at present from 

 chemical grounds. But looking at the blood itself as organic, or 

 vitally compounded and mechanical, it is easy to see, that in the 

 place where it has to yield up any of its constituent parts that the 

 successive organisms require, it must lose its principle of combina- 

 tion in order to allow it to pass into other forms. In short, it must 

 undergo a vital decomposition for the purposes of the body; and if 

 its arterial glitter depends upon the spirit shining through it as 

 through an organic face, then when this spirit escapes and comes 

 out, and the subordination of parts is lost, the comparatively life- 

 less hue of venous blood will be assumed. Furthermore, we may 

 infer that the nerve spirit, which is the charioteer of the globule, 

 and its principle of organization (p. 55), when its heat or desire of 

 blood-organization is ended, and when it comes down among the 

 other elements, will kindle with that sensible heat which is expe- 

 rienced in the lowest sphere ; in other words, that in the body, the 

 intellectual or organific heat is in a lower degree the parent of true 

 animal heat. This we find to be the case on a large scale by the 

 glow of zeal, passion and affection in the cheeks and the body; and 



