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combinations of properties constituting the life of the respective 

 seats are capable of assimilating and maintaining themselves by their 

 relation with the blood, independently of other spiritual properties. 

 29. But although an organic spirit may exist and assimilate 

 independently, yet the spirit in every sphere cannot always be said 

 to be perfect in that sphere; that is, although, independently of the 

 spirit of any other sphere, an organic life, according to our defini- 

 tion, would be maintained, yet the attributes of this life may be 

 modified or suspended by an interruption which relates only to 

 spiritual communication, and which is no interruption to the blood. 

 Some powers of muscles (which will hereafter be appropriately 

 designated) we know to depend upon a communication with the 

 brain; yet the organic life of those muscles may be preserved under 

 a total division of the nerves. So the secretion of the stomach is 

 said to be prevented by a division of the eighth pair of nerves, &c. 

 But in these cases, and especially in the latter, it is not to be inferred 

 that the life, or even the power of secretion, is wholly dependent 

 upon a nervous centre; for we Hnd that where there is already the 

 predisposition, the effect of it does not take place for want of a mere 

 stimulus,* and this might be furnished by a hundred things indiffe- 

 rently. As when the mouth is, dry, saliva might be made to flow by 

 sugar, salt, tobacco, by chewing a stick, &c. Hence it has been, 

 absurdly perhaps, inferred, that agents, capable of re-producing a 

 secretion suspended in consequence of a division of nerves, have 

 been the full and total identity of the cause of the secretion, as 

 electricity, &c. We find, however, from these views, that the sub- 

 ject is liable to be considered in the modes before proposed, viz. 

 influence of spiritual properties of seats by privation and by com- 

 munication. It remains that we should sum up the criteria deduced 

 from some of the illustrations of the present article by which the 

 inquiry is to be conducted. 



1. A simple division of a structure may destroy the life of an 

 inferior part of the same structure; but if a connection with living 

 structures is preserved by blood-vessels, this rarely happens except 

 by processes of disease. 



2. When a secondary, happens in consequence of a primary, 

 injury or affection, if it is ascertained that the life of the secondary 

 seat may preserve its identity, &c. when separated from the primary, 

 it is to be inferred that there is no dependence between them, and 



* The word " stimulus" is employed to denote a cause capable of producing 

 certain effects upou a certain predisposition, by properties common to it, and 

 many other substances which are made to appear different by their combina. 

 tions; thus, brandy, ather, laudanum, blisters, spurs, whips, &c. are all 

 stimuli, that is, these substances, though different, have, so far as the effect is 

 common, a property in common which produces it. This matter has beeu 

 explained in the chapter on Causation, where, treating on the various associa- 

 tions to which similar properties are liable, it is also explained, that notwith- 

 standing these different associations, the properties in question may produce 

 their proper effects upon their other relations, unless the associated properties 

 are so related also as to counteract tins end. 

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