CATHARTICS. 183 



salty taste. Soluble in 2^ parts of water, almost in- 

 soluble in alcohol. Used as a cardiac tonic and al- 

 terative in weakened heart's action. Externally — as 

 collyrium in conjunctivitis and wound dressing; ^ to 

 2 parts to 100 of water. Professor Dieckerhoff's re- 

 cent experiments on horses, cattle, and sheep show 

 that it is a powerful and rapid purgative, but which 

 must be cautiously employed since clinical experience 

 and observation of its actions are still incomplete. It 

 is said not seriously to affect either respiration or 

 circulation when given in doses large enough to cause 

 catharsis. The impure chloride of barium has long 

 been used as a "rat poison." Dose: H., 3ss.-iij., 

 per os; if intravenously, gr. v.-xx., dissolved in dis- 

 tilled water. N.B. : Intravenous injections require 

 great care ! 



Cholagogue Purgatives. 



PodoplujUum, May-apple, the rhizome and rootlets 

 of Podophyllum peltatum or mandrake (natural order 

 Berberidese). Its active principle is: 



Resina Podophylli, resin of podophyllum. Dose: 

 H., 3i.-ij.; D., gr. ss.-ij. 



On horses and cattle its cathartic action is inferior 

 to that of other purgatives, but its cholagogue effects 

 are undoubted ; anthelmintic properties are also at- 

 tributed to it, and in the dog it sometimes causes 

 nausea and vomiting. 



Hydrargyri Chloridum 3Iite, calomel; Hydrar- 

 gyrum cum creta, gray powder; Massa Hydrar- 

 gyri, blue mass. See under Hydrargyrum. 



