905 



Modus Operandi of Medicinal and Morbific 

 Agents. 



It is still a question among physiologists, whe- 

 ther these agents operate primarily on the blood, 

 or through the medium of the nervous system, 

 by what has been called sympathy, as maintained 

 by Stahl, Hoffman, Baglivi, Gaubius, Cullen, 

 Brown, and a large majority of modern patholo- 

 gists. That the brain and nervous system are 

 more quickly and powerfully affected by the 

 mephitic gases and narcotic poisons than any of 

 the other organs, cannot be denied. But we have 

 already seen that all parts of the body are formed 

 from, and vitalized by, the blood, which is abso- 

 lutely essential to every operation of the animal 

 economy, and more essential to the healthy 

 activity of the brain than any other part of the 

 system, consequently, that whenever the vital 

 properties of the blood are impaired, the nervous 

 system is the first which becomes diseased.* 



It was long ago ascertained by Fontana, that 

 opium, poisons of the viper, ticunas, and laurel 



* For example, we have seen that about five times more blood 

 is sent to the brain, in proportion to its weight, than to the body 

 in general. The consequence of which is, that it is the first 

 organ to suffer from loss of blood, or from whatever impairs its 

 vital properties. Hence the prevalent opinion of pathologists, 

 that the remote and exciting causes of fever produce their primary 

 effects on the nervous system. 



