ON OPIUM. 347 



'it is not under this expectation that I take up the pen, for rjTects'< 

 how much soever may have been feli'ected, something y^t ?^-""^ ^^tenf 

 remains to be done by the diligent and patient enquirer, 

 and, though nothing could be gained beyond a confirmatioii 

 of established opinions, yet if this be done through the 

 means of accurate and repeated experiments, something is 

 added to the stock of information, and it must be considered 

 at the least as possessing a relative value. 



These experiments are not ho^vever destitute of some 

 novelty in the arraagement, and they will be found to ex- 

 hibit, in a clear analytical succession, the effects produced 

 by opium upon the different parts of the animal machine. 

 But it is not clear by any moans, that the physiologists of 

 this day are agreed upon many points, which will be 

 brought forwards in this essay, and more is required to be 

 done, before the subject can be considered as exhausted. 



The humoral pathology, which had for a long space of 

 time occupied the schools of medicine, had no sooner been 

 ealled in question than a variety of opponents arose in 

 every quarter against it; the new opinions being clothed 

 in professional authority and enforced by the learning and 

 genius of several private teachers, the tide of opinion flowed 

 in a contrary direction, and it became the fashion to ac- 

 count for all, or most of the deviations from a state of 

 health in the animal body, from some primary alteration 

 in the condition of the solids. In many points the ad- 

 vocates for the new doctritujs were notwithstanding at issue 

 with each other, and the memorable contest betwixt Ilallcr 

 and Whytt, respecting the origin and nature of irritability, 

 opened the physiologist new sources of enquiry and laid 

 new foundations for future improvement. The agency of 

 the nervous system, which was still necessary for the ex- 

 planation of most of the phcenomena upon the theory of 

 diseased solids, began at length to be exploded by the ad- 

 vocates of another yet more refined and simplified, v.hich 

 the creative genius of John Brown ushered into the schools 

 of physic. 



This doctrine rejecting the explanation of diseases upon 

 partial and confined theories, attempted to refer all the 

 rarious changes in the human body to one genjeral law. 



He 



