The preface to the British Pharmacopoeia, 1914, contains the following statement, which, though not legally binding upon pharmacists, represents customary practice:

The medical practitioner will exercise his own judgment and act on his own responsibility in respect of the amount of any therapeutic agent he may prescribe or administer. Where, however, an unusually large dose appears to be prescribed, it is the duty of the pharmacist or dispenser to satisfy himself that the prescriber's intention has been correctly interpreted.

In the German Pharmacopoeia a table of maximum doses of certain powerful medicines is given, and if the pre-scriber desire to exceed the amount there set down he is required to mark the quantity. If this is not done the dispenser is held responsible for the consequences if he dispense the dangerous dose. Two curious cases were mentioned by Dr. Hager. In one, an extra dose of cyanide of potassium had been ordered, and the prescriber had several times underlined the quantity. The patient died, and the dispenser was condemned to a year's imprisonment because he had dispensed the medicine without the proper mark (!) being attached. In the other case, the physician meant to order 4 grammes of chloral hydrate, and he should have written grm. 4.0. He omitted the decimal point, however, and the dispenser gave 40 grammes. At that time chloral hydrate was not included in the German Pharmacopoeia, and therefore was not in the table of dangerous substances. But the dispenser was sentenced to a long term of imprisonment.

It is indeed a constantly recurring difficulty to dispensers of limited experience to know whether certain quantities prescribed are not either unusual or dangerous doses. The British Pharmacopoeia doses 'are not authoritatively enjoined as binding upon prescribers . . . and represent . . . the average range of the quantities which, in ordinary cases, are usually prescribed for adults.' Provincial dispensers may generally feel safe when the autograph prescription bears the businessstamp of some London house. It has probably been dispensed many times; and the pharmacist is advised not to indicate by his manner, still less by any direct question to the patient, that there appears to him to be anything remarkable in the prescription which he is called upon to dispense.

But do not follow the example of the London house if you think that there is a possibility of poisoning the patient. For instance, a prescription was given in to a provincial house which ordered a large dose (about an ounce) of aq. laurocerasi. It bore the stamp of a leading London house, and appeared therefore to have been taken by the patient with safety. Not being satisfied, the provincial chemist inquired about the matter, and found that the London house had omitted a considerable quantity of the aq. laurocerasi. This incident emphasises the aphorism: If a prescription be altered it should be so marked.

Many examples of large doses could be cited. Two grains of extract. cannabis indicae has been given every two hours in a case of tetanus, but the case was watched by several medical men. Teaspoonful doses or more of bismuth sub-nitrate are common, either as a cure or to coat the stomach for x-ray purposes. In some cases ordinary doses of narcotics cause great excitement. For example, 30 grains of chloral hydrate has made a man most obstreperous, but drachm doses induced sleep. A well-known authority states that he has seen 5 ounces of the juice of conium ordered and taken daily, 1/2 grain of pure hyoscyamine for a dose, and 1 drachm of tincture of Indian hemp three times a day. The patients who took these doses were, of course, under special observation.

The following prescription was given to be dispensed as a draught:

No directions were given. On the pharmacist expostulating with the customer as to the largeness of the dose of iodide, it was most strenuously affirmed that it was for one dose only. It had been dispensed before for a friend, who lent it to the customer. Probably there was here a little attempt at economy, the customer intending to add the necessary water.

At the Minor examination on one occasion, a candidate got the following prescription to dispense:

Fiat haustus. Statim sumendus.

The candidate told the examiner before compounding the draught that it should not be dispensed, because it contained too much opium. He was told to dispense it as written, and did so. Before he left the dispensing-counter, the examiner asked the candidate what he had to say about the prescription, and the candidate repeated his objection to the large dose of opium, which he considered to be a probably fatal dose. 'Quite right,' said the examiner;' and what would you do in the circumstances?' 'Consult the prescriber,' was the reply, which satisfied the examiner, and the candidate passed.

The foregoing fairly indicates how the dispenser should act when exceptionally large doses confront him. Nothing about the matter should be said to the customer, but delay should be secured if possible in order that the prescriber may be consulted. This is the more difficult part of the matter, because some medical men strongly resent any interference, as they consider it, by the pharmacist; the fact being that in most of such instances they feel hurt that their blunders have been detected. The pharmacist should have little difficulty in knowing what to do with such men's prescriptions, for if the prescriber places his assumed dignity before the comfort and, maybe, life of his patient, the pharmacist may reasonably act upon his own responsibility, taking the British Pharmacopoeia as his guide in respect to doses. See the note on ' Errors in the Prescription.'

General Directions are as a rule unsatisfactory and often lead to mistakes. We have been asked, If a doctor sends a prescription for a mixture (not dangerous) marked 'Special: To be taken as directed,' is he justified in condemning the dispenser as an unpardonable offender for sending the mixture to the patient without further instructions respecting dose? The censure is unwarranted. 'To be taken as directed' implies that the prescriber has given directions, but it is not uncommon to find that the prescriber has omitted to do this, and for that reason it is always safe for the dispenser to ask the customer how the medicine is to be used, and so ascertain whether the directions are sufficient or not. If the mixture is dangerous and the directions have been omitted, a polite note may be sent to the doctor, or the customer may be asked to call upon him for instructions.