INTRODUCTION. 



sionally more liable to mislead than even the 

 deductions of theory, if they are regarded by a 

 mind neglecting to generalize the facts presented, 

 to note the relations between objects that are 

 manifest, or to refer those phenomena, that have 

 no obvious connexion to explain them, to the 

 most probable or general law of the animal eco- 

 nomy. This method of investigating the laws 

 of the system has been entirely neglected by 

 WILSON PHILIP, and to a certain extent by 

 BRODIE, and others engaged in similar physiolo- 

 gical pursuits. The former gentleman divided 

 the par vagum, and found, as a consequence of 

 this operation, that the function of digestion was 

 very much retarded or destroyed : from this effect 

 he concluded, that digestion depends on 7iervous 

 influence; but, what is somewhat extraordinary, 

 while he observed the animal breathe with 

 great difficulty while he remarked its temper- 

 ature to diminish 15 or 20 degrees, nay, even 

 after the death of the animal, when the lungs 

 exhibited the colour and congested appearance of 

 the liver he never for a moment seemed to ima- 

 gine that the proper performance of respiration, 

 and the normal circulation of the blood, tvere con- 



