302 



to think that the liver obtains properties of the regular dependent 

 kind, perhaps from a nervous centre ; at all events, \ve cannot prove 

 that the first processes of the predisposition to * tubercle origi- 

 nated in the liver, unless we can first prove that its life is inde- 

 pendent of all other seats, and that the properties determining the 

 earliest processes of progressive change have been allied to the 

 assimilating life of the liver from its first development in the uterus. 

 31. But not to encumber a plain argument with subtleties, 

 the preceding exposition of the force of the evidence is sufficient 

 to shew that such a doctrine cannot be rationally entertained ; fur- 

 ther, that it must be positively rejected. There is, however, one 

 other argument, cited perhaps in favour of the doctrine, upon 

 which also we might bestow a short notice: this argument is de- 

 duced from the operation of remedies, and, fairly stated, is as fol- 

 lows: the diseases which are affirmed to be dependent upon the 

 digestive organs get well (sometimes) under the operation of reme- 

 dies which are designed to correct their disorder; which fact, it 

 may be continued, must be allowed to be a proof of their depen- 

 dence, <S:c. The question is, not what these remedies are de- 

 signed to do, but what they actually do; and as for what this argu- 

 ment must be allowed, we shall examine a little further before we 

 allow it any thing. 



32. Suppose a disease of the skin to be cured by blue pill; 

 suppose that the alvine excretions become regular and good; sup- 

 pose that the secretion of bile is improved, that the appetite re- 

 turns, that the tongue becomes clean, and that the disease of the 

 skin gets better, and finally well, under the use of the blue pill; 

 does it therefore follow that the disease of the skin was produced 

 by any of, or all these circumstances belonging to the abdominal 

 viscera? the operation of the blue pill may be upon a seat which is 

 only related with the liver, bowels, &c. as well as directly upon 

 these viscera; or the disease of the skin may be cured, as by a 

 remedy which is applied to its seat through the medium of the 

 circulation; there may be no dependence at all between these 

 phenomena, but they may all cease, as accompaniments only, 

 under the operation of an agent whose properties are remedial in 

 regard to them all; or, granting further all that is required, viz. 

 that the blue pill acts exclusively upon the liver, stomach, bowels, 

 &c. and that the disease in the skin gets well under the mercurial 

 excitement produced in these parts, yet it does not follow that the 

 disease of the skin was produced by their disorder, for the preter- 

 natural affection produced by the mercury may have a curative 

 relation \vith the disease of the skin; the mercury may operate 

 upon a common principle of change, the preternatural affection 

 of the abdominal viscera may cure the disease in the skin in the 

 same manner as mustard plasters on the soles of the feet may cure 

 gout in the head, or as a blister on the side may cure a pleurisy. 

 Yet in these cases, which are the most level to our experience, we 

 do not set up a causative relation: no one will employ this, which 



