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1st, The spirit residing in these surfaces receives a modified 

 supply of blood, as by the general injury, the compression, &c. 

 which the vessels must sustain by a breach in a structure before 

 continuous; or, 



2nd, The mechanical change of the structure must directly pro- 

 duce a change in the condition of the spirit; or, 



3rd, The spirit is directly modified by the confusion, or mixture 

 of spiritual properties, which before held distinct spheres. 



1. It is probable that the disordered circulation, necessary to a 

 surface produced by mechanical separation, may (as the circulation 

 is every where so intimately connected with life) contribute to pro- 

 duce that change of the spirit upon which the consecutive pheno- 

 mena of the injury depend. 



2. It has. been shewn in the chapter, " Relations between Vital 

 and Mechanical Properties," that a mechanical agent can have no 

 direct relation with life. Hence, we can assign no agency in these 

 phenomena to mere mechanical influence, except that mediate one 

 implied in our 1st and 3rd alternatives. 



8. The sphere of life in every seat is maintained by the alliance 

 of the spiritual properties with the organic particles of such seat. 

 Hence, if the organic particles are disturbed or displaced, the 

 spiritual properties suffer a corresponding disturbance, and those 

 which should occupy distinct spheres become mixed. Of the ten- 

 dency of spiritual properties of one seat to modify those of another, 

 we have seen enough in the preceding pages. The modes in which 

 such modification may be produced in the present instances are, 1st, 

 by direct change in the life of the separated surface, by union with 

 heterogeneous properties; 2nd, by indirect change, by disturbed 

 relation between the life and the nutrient material of such seat. 



6. According to the nearest and most frequent analogies, I 

 should say that mechanical injuries produce their effects upon the 

 principle of life, commonly, by the confusion of the life which should 

 hold distinct spheres, in consequence of its alliance with the matter 

 which is disturbed merely by a mechanical relation; and by the 

 change which life suffers by mechanical injury of blood-vessels, the 

 state of which life depending upon a regulated supply of blood, 

 suffers also a change, in agreement with the preternatural relation 

 thus mechanically occasioned. From the suddenness with which 

 life is affected by mechanical injuries, it appears as if the spirit 

 suffered most commonly in the way described, without the inter- 

 mediate relation of a disordered circulation, as in cases of wounds, 

 and more especially those happening in the brain, spinal marrow, or 

 nerves. Indeed, from some of these instances, a pretty unequivocal 

 argument might be deduced in favour of this mode of the effects of 

 mechanical injuries; but it is sufficient to have suggested these 

 modes, and to add, that by these modes a state is established which 

 produces further effects, by processes, generally analogous to those 

 of spontaneous disease. 



