SUBSTANCES ACTING ON RESPIRATORY SYSTEM. 491 



as Opium, but, as we have seen, not without considerable 

 risk. The greatest discrimination must, therefore, be exercised 

 in having recourse to these remedies, and the routine use of 

 them is to be deprecated. Indirect measures, including the 

 removal of the cause of distress, and external application to the 

 chest, are alone to be employed if possible. 



SUBSTANCES WHICH ACT UPON THE EESPIRATOB.Y SYSTEM. 



