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CHAP. V. The Spleen. 





1. THE spleen i enumerated among the preparatory 

 organs, because from its situation and connexions it appears to be- 

 long to the system of the chylopoietic viscera. It is supposed that 

 its use, if it has any, is one subservient to the preparation of food. 

 but there is no absolute proof that it contributes any thing to this 

 purpose. The same might be said of the liver; at least, as remarked 

 in the last article, it is not ascertained what share bile has in those 

 intestinal conversions which are necessary to the maintenance of life. 

 The analogy holds good no farther than that there is mutually an 

 absence of demonstrative proof: but, in the case of the liver, a 

 product of its function is perceived, the destination of this product 

 may to some extent be traced: it is seen to mix with food, &c. and 

 that it tends to accomplish some useful purpose in the system, is 

 believed, agreeably with an extensive experience, that no regular 

 operations of this kind, which we have been enabled to understand, 

 take place in animal bodies without a reference to such future 

 purpose. The spleen furnishes no product: and as we are not ac- 

 quainted with the manner in which any similar viscus extends its 

 function beyond itself, we are left to conjecture concerning the mode 

 in this instance, without the support of any, or but a distant, analogy, 

 deduced from the phenomena of animal life. 



2. We are nevertheless disposed to assign some use to the 

 spleen, on a ground which differs from that on which we assign an 

 use to the liver in these respects, viz. that the use of the former is 

 supposed from a general analogy, and that of the latter from the 

 particular analogy which obtains between it and other secreting 

 organs. We observe in a general way, that there is no part of an 

 animal body without its use, and when an apparent exception occurs, 

 in agreement with our general experience, we presume that our 

 ingenuity has been insufficient to discover the designs of Nature, 

 rather than that she has made the object of our suspicions in vain. 

 Let us, however, having stated the grounds by which we are induced 

 to seek a function of the spleen, take a short view of the more par- 

 ticular manner in which the inquiry respecting it has been conducted. 



$ 3. The spleen, as is well known, has been removed from dogs, 

 and the animals have not only survived but have appeared to suffer 



