364 ESSAYS AND OBSERVATIONS 



though, perhaps, we may not be able to 

 perceive or afcertain their nature by our 

 imperfect fenfes : I only alledge, that the 

 eftedls operated on the fluids by one dofe, 

 or by one over-dofe, are inconflderable, 

 when compared with its effecSls on the 

 nerves of the circulating fyilem, 



12. V/Eare to confider, that the nerves 

 cf the heart, and large branches of the 

 vafcuiar fyftem, affedled by medicine;^ 

 abforbed and conveyed with the blood, 

 will influence, by fympathy, other nerves 

 of the body, to Vv'hich thefe medicines 

 may not perhaps be able to penetrate 

 through the very fmail veiTels. 



33. Medicines circulated with the 

 blood, will probably affedl fome organs 

 more readily than oihers, owing to the 

 very different termination of their vef- 

 fels, and various feeling of their nerves. 

 Hence, v»^e may fuppofe, there are, in na- 

 ture, medicines which, with ftridl pro- 

 priety, might be termed cephalic^ pulmonic^ 

 hepatic^ JpleniCy ^c. though hitherto thefe 

 names have been applied with fo little 



precifion, 



