THE PRESCRIPTION. 25 



they neutralise the action of each other in certain 

 directions, they are left mutually free to affect other 

 parts of the system. Thus, calomel combined with 

 opium prevents it from causing constipation, whilst it 

 does not interfere with its action on the brain ; and 

 the opium, in turn, prevents the calomel from purging 

 the patient, whilst it allows the mercurial to act as 

 an alterative. Most purgative pills contain correctives 

 or carminatives, which moderate the violence of peri- 

 stalsis and prevent -pain. 



8. The Prescription. A prescription consists of 

 five parts : The superscription, consisting of a single 

 sign, R, an abbreviation for recipe, "take"; the inscrip- 

 tion, or body of the prescription, containing the names 

 and quantities of the drugs ordered ; the subscription, 

 or directions to the dispenser ; the signature, or direc- 

 tions to the patient, headed by Signa ; and, lastly, 

 the patient's name, the date, and the prescriber's name 

 or initials. In what may be called a classical pre- 

 scription, it was customary to arrange the constituents 

 of the inscription under four heads, viz. the basis, 

 or active drug proper ; the adjuvant, or substance 

 intended to assist, and especially to hasten, the action 

 of the basis ; the corrective, to limit or otherwise 

 modify the same (commonly a carminative) ; and the 

 vehicle, or excipient, to bring the whole into a con- 

 venient, pleasant form for administration. 



To take an example : 



Superscription. R 



'Ferri et Ammoniae Citratis, gr.v. (basis). 



Liquoris Ammoniae Fortioris min.jss. (ad- 

 Inscription. jr 



Spiritus Mvristicae, min.vj. (correct h;]. 



Infusi Calurnbse, ad ^i. (vehicle or excipunt}. 

 Subscription. Misce. Mitte doses tales viij . 



<>>-. Signa Two tablespoon fuls twice a day. 



Patient's name. Practitioner's name 



Date. or initials. 



