Day: October 6, 2026

There is a brown glass bottle, photographed in museum collections, with a label that reads Cannabis Indica. Underneath, in smaller type: Fluid Extract. Physiologically Tested. And along the bottom edge: Guaranteed under the Food and Drugs Act, June 30, 1906. It was made by the American Druggists Syndicate, a co-operative of retail chemists that manufactured its own goods in Long Island City, and it dates to somewhere around 1910 to 1916. Most people look at a bottle like that and see a curiosity. A bit of Victorian strangeness. We looked at the label and saw a set of promises. Every phrase on it was doing a job. Each one was a claim about identity, strength, or honesty — the same three claims a bottle of CBD oil makes on a shelf in Ireland today. So this article takes the label apart, phrase by phrase, and asks a simple question of each one: what did it actually mean, and how does it compare to what we can do now? Some of the answers are flattering to the present day. One of them isn’t. 1. The Bottle: What It Was and When It Was Made Start with the dating, because the label dates itself. The phrase Guaranteed under the Food and Drugs Act, June 30, 1906 could not appear before mid-1906, when the US Pure Food and Drugs Act was passed. That is the floor. The ceiling comes from the pharmacopoeial standard. The label names the USP eighth revision, which was the official American drug standards book from 1905 until the ninth revision replaced it on 1 September 1916. That is the ceiling. So: c.1910–1916, give or take. Which is worth pausing on, because of what it isn’t. William Brooke O’Shaughnessy, the Limerick doctor who introduced cannabis to Western medicine, published his Calcutta trials in 1839 and died in 1889. This bottle was filled roughly seventy years after his paper, and twenty-odd years after his death. It is not his bottle. It is the industry his work created, three generations on — mass-produced, federally regulated, and sold by catalogue. What a “fluid extract” was A fluid extract was the most concentrated liquid preparation in the pharmacopoeia. The standard was one part by weight of crude drug to one part by volume of finished extract — so one gram of dried herb yielded one millilitre of extract. A tincture was far weaker, typically a tenth of that strength. Fluid extracts were the professional-strength preparation: a pharmacist diluted them to make up a prescription. The solvent was alcohol, usually with water. Cannabis resins do not dissolve in water, so alcohol did the work — the same reason modern extraction uses ethanol or CO₂ rather than water. And the 1906 Act required the alcohol percentage to be declared on the label. That was one of its central provisions: a list of named substances, alcohol among them, had to be disclosed if present. This label declares 60 per cent. So a customer in 1912 could read the alcohol content off the bottle. That is a disclosure requirement most food supplements in Europe still don’t carry. 2. “Physiologically Tested” — They Tested It on Dogs This is the phrase that stops people. Here is why it was there. In 1912, nobody could measure what was in cannabis. Cannabidiol was not isolated until 1940. THC was not characterised until 1964. There was no chromatography, no mass spectrometry, no way to put a number on a bottle’s contents. But cannabis strength varied enormously between harvests — Irish and British pharmacists had been complaining about exactly that since the 1840s. A bottle you couldn’t measure was a bottle you couldn’t dose. So the industry measured the effect instead. In 1908, two Parke-Davis pharmacologists, Houghton and Hamilton, published a method for standardising cannabis by giving it to dogs and observing the dose at which the animals became unsteady on their feet. Loss of coordination was the endpoint. It was visible, it was gradual, and it was reproducible enough to compare one batch against another. By 1916, this was the official standard. The United States Pharmacopoeia ninth revision required that fluid extract of cannabis produce incoordination when administered to dogs in a dose of not more than 0.03 mil per kilogramme of body weight. Read that again. The specification was not a percentage of anything. It was a dose at which a dog should wobble. The procedure The published method is unexpectedly precise about everything except the chemistry. Fox terriers were preferred — small, consistent in size, and familiar enough with the handler that nervousness wouldn’t be mistaken for drug effect. Two dogs per assay, because one animal’s reaction proved nothing. Fasted for twenty-four hours beforehand, so stomach contents wouldn’t slow absorption unpredictably. Tested in a quiet room, each dog separated, because an excited dog looks like an affected dog. Observed by the same person throughout, since the whole measurement was a judgement call about when an animal became unsteady. Three days’ rest between tests on the same animal, because tolerance built up and a tolerant dog would make a strong batch look weak. Every one of those details exists to control a variable in a test whose instrument was an animal’s gait. The dogs were kept, rested and tested again — which is precisely why tolerance was a problem the method had to work around. No laboratory would be permitted to do this now, and that is the right outcome. What the profession thought of it They were not satisfied. That’s the part worth knowing. The United States Dispensatory of 1918 — the standard reference of the day — said the assay gave the preparation a certain indefinite amount of physiological action, and concluded that it was impossible to assign the proper dose. That is a profession writing down, in its own flagship reference book, that its best available standard wasn’t good enough. They used it anyway, because it was all they had. What replaced it High-performance liquid chromatography. Put