A skirmish across the Pond

Readers may be interested in a recent exchange of views between Clay Rogers, a journalist with a newspaper in Iowa, and Paul Trusten, Vice President of UKMA’s sister organisation in the USA.

From 3 March 1969, it became illegal in the UK to use any system of weights and measures other than the metric system for dispensing prescriptions – older readers may remember being issued at the time with a 5 mL plastic spoon. It may, therefore, come as a surprise to learn that in the USA medieval measures such as the grain and the scruple were still in use in pharmacies until recently.

Paul Trusten uses his experience with these archaic and irrational measures to promote the completion of the metric changeover in America. Of course, the world has moved on and very few medicines nowadays are made up to order in the local pharmacy. But the debate on measurement systems continues, both in the USA and in the UK, and Paul has taken this opportunity to make a useful contribution.

Here is is the link to Clay Rogers’ article:


This is Paul’s response of 24 April:

Dear Mr. Rogers,

Thank you very much for your column opposing U.S. metrication. I appreciate your focused opinions. You are eloquently passionate about your stand on the subject.

It was hardly fanaticism or a desire to be clever that drafted me into the quest for a metric America. Neither was it out of partisan politics or intellectual conjecture. It was patient safety in healthcare.

About 40 years ago, while still a pharmacy student, I was working through a homework problem on calculating weights to be used in the measurement of ingredients in the compounding of prescriptions. There was a page in my workbook divided in half. On the left was the beautiful, romantic system of scruples, drams, and grains that, to me, left much open to error. On the right was a series of those toe-counting decimal numbers of grams, and the weights were to be added with one instruction: “add everything to get a total.” How simple and how clear, I thought, and indeed, how SAFE, especially if it was being used exclusively.

From this starting point, I grew up to believe that a country using one system of measurement is a safer country to live in. This is not a matter of accumulating data on the subject, but simply the idea that there is a chance that our non-metric culture alone could kill people.

A number of medications are dosed based upon the patient’s weight, or, a little more subtly, a patient’s body surface area. If the outside culture generates an opportunity to confuse measurement units, or if a conversion is done incorrectly, a massive overdose can result. If this occurs with some powerful anti-cancer drugs, we have the irony of the instrument of lifesaving becoming transformed into the instrument of life shortening. I do not think that preventable accidental death is romantic at all, nor should it be subservient to the insistence upon romance. That is not Orwellian, but human.

But, the metric system itself grew on me. I like its decimal millimeter simplicity as opposed to the constant need to interpolate eighths vs. sixteenths of an inch on an inch rule. And, as a citizen in a standards-loving nation, I wonder why THIS standard, one of measurement has not been adopted fully. This isn’t “progress”, a word often brandished as reminiscent of trying to pave over the Grand Canyon. For our country, it represents catching up. The metric system of measurement is ordinary, not radical.

I am 63 years old, and I share with you much of the same sadness in what I view as the decline of what is beautiful to me, too. I read your list of complaints, and I said to myself, “check, check, check.” But, to shun long-overdue convenience when it is possible, and worse, to tolerate confusion even in the face of danger, is ugly.

The term for a planned changeover to the metric system as the Nation’s sole measurement standard is “metrication”, not “metrification”, because there is no “if” in metrication, only “when.”


Paul Trusten, Registered Pharmacist
Vice President and Public Relations Director
U.S. Metric Association, Inc.
Midland, Texas, USA

Readers who are curious about Imperial measures may be interested to know that:

3 scruples          = 1 drachm
8 drachms         = 1 ounce apothecary or troy (31.103 5 g)
12 ounces troy  = 1 pound troy
16 drams            = 1 ounce avoirdupois (28.349 5 g)
7000 grains       = 1 pound avoirdupois

10 thoughts on “A skirmish across the Pond”

  1. Paul may have encountered them in pharmacy school, but from the consumer side, I’ve never seen a scruple, and the grain died out a few decades ago (somebody will occasional label generic “no-name” aspirin as 5 gr, not 325 mg, but “it’s not professional” and I wouldn’t buy it). However, the teaspoon (5 mL) has hung around as a dosage in liquid medicine, and there is quite a campaign currently to eliminate it due to dosing errors and the use of tableware not measuring spoons (which frankly are not a good shape for administering medicine, anyway).


  2. I apologize if my letter to Mr. Rogers implied that the apothecary system of measurement was still in general use in U.S. healthcare “until recently.”

    The calculation exercise in my story was already archaic when I performed it in 1974. Pharmacy education at the time had to include this system because it was still used by some practitioners to write prescriptions. But, it has been more than 40 years since I have even seen an oblique reference to an apothecary fluid ounce in routine practice, and even so, that may have been only once or twice .

    Some drug products still reflect the old system. Anyone who takes desiccated thyroid tablets (Thyroid USP) will notice, if they got a stock container from their pharmacy, that the label reads (and falsely), “thyroid 1 gr. (60 mg)” (1 grain is approximately equal to 65 mg, not 60 mg). Of course, the reason why we have aspirin and acetaminophen tablets in 325 mg strengths is due to a conversion from five grains. And, one may encounter phenobarbital 97.2 mg only because the tablet strength is converted directly from 1 and 1/2 grains. Finally, is odd but true: prescription-only oral liquids are often still sold in legacy stock bottle volumes of one pint or eight fluid ounces.

    In 1995, the U.S. Pharmacopeia, the standards-setting organization for pharmaceuticals in the United States, canceled any remaining recognition of apothecary units in U.S. healthcare. Except in the minds of a few surviving healthcare providers, it has no official standing in America. Good riddance to bad rubbish!


  3. In the light of the 150 year saga of US metrication, it seemed to me that ‘recent’ might include the last 25 years. But it is good to hear that this important area is now fully metric – there are those in the UK who would have us believe that English units are used for almost everything in the USA.

    I am not surprised about the survival of irrational metric sizes. Here, the major supermarket chains still sell fresh pasteurised milk in 1, 2, 4 and 6 Imperial pint containers.


  4. Derek,

    Unlike the UK, most consumer goods in the US must be dual labeled, both metric and Customary. The law treats them as precisely equal but sensible Customary fill is a (slight) majority. Things come in three sizes:
    *Sensible Customary amount
    *Sensible metric amount
    *Completely irrational sizes: One example from my frig is labeled 15.5 OZ 439 g. The conversion is correct, but neither size is “sensible,” requiring three significant figures.

    These are at least in rank order, and by percentages, maybe 50/40/10, or 60/30/10, something like that.

    There are a few exceptions that allow english units only, but most are english AND metric. Notable exceptions:
    *Beer (that should be familiar)
    *Meat in either standard or random weight packages (because it is regulated by USDA)
    *Any item in random-weight package or weighed-at-retail (produce and deli.)
    Note that produce in a standard weight (or volume) package must be dual labeled.

    I am fairly sure that ACWM and BWMA (when they visit) must have eyesight problems and miss the compulsory metric. To be honest, a majority of Americans ignore the metric and use the Customary in making their decisions.


  5. @John Steel
    I think I can explain the irrational size of 15.5 oz. I think this is to allow for outer packaging, such that a palletable packaged load would come out as a rational number of lbs equaling the number of units for shipping.
    I have noticed this a few times with American goods. Nice for transport (except shipping is done in cu. ft), never mind the end user.


  6. Another bit of interesting dis-education for me. I always thought that the use of ‘gr’ in American was the misuse of the symbol for ‘gram’. I had never even thought of ‘grains’, it would mean absolutely nothing to me. So a simple error of reading ‘gr’ as ‘g’ would be a 15 times overdose or under-dose.


  7. @BrianAC,
    That would make sense for some kinds of product. In this case, product is in a glass jar.
    I think it is more likely that glass jars are standardized by volume, but this product must be sold by weight, by law. Different products in the same jar have differing density and in this case the result seems a bit nonsensical. I was just demonstrating that the fill doesn’t have to be a nice, round number in either unit system and sometimes isn’t. Compared to the UK, we have very little “standard sizes” legislation, wine and spirits are the only examples I can think of. Manufacturers (or their organizations) seem to agree among themselves so the proliferation isn’t as bad as you might expect, given no laws on the subject, but more than the UK might accept.


  8. @ John Steele

    Following an EU directive a few years ago there are now very few “prescribed quantities” for packaged goods in the UK. As far as memory serves me, the main or only exceptions are wine and spirits (as in the US). This has led to the problem of manufacturers reducing quantities by small amounts but keeping the price the same. The argument for abolition was that the customer could judge value for money by looking at the “unit price” that must be displayed on the shelf label. However, a survey by the former Consumer Council found that unfortunately the majority of consumers either do not understand the concept or cannot read the small print.


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