Of course this is privileged information. I could easily have found the data and then pretended to have made the prediction. Indeed the match is uncannily close, given I spent less than a second before coming to a conclusion - and uncanny means literally/prosaically incredible. The idea is to point at what to look for in yourself, rather than for you to believe I did in fact do this. Secondarily, when I say one of my predictions came true, I mean I observe something like this.
It's oft repeated that nicotine has a lethal dose of 50mg. When I first saw this, today, I assumed they had misread the units - surely, that's supposed to be mg/kg? Google gave me the CDC, which I assumed had dropped the /kg, as it uses mg/kg everywhere else, including the immediately following example parenthetical. On being prodded, I looked further down the search results and found this and this, showing the myth is definitely out there in the wild. Because the CDC was inconsistent about units, I predicted that someone had dropped the units, and subsequently been seminal. (And that given that the human dose is rated as exactly the rat dose, it's probably basically a guess, not even informed by clinical case studies.)
Then I followed the link in that latter link.
"Some of these effects resemble typical symptoms of nicotine overdosing, but 1–4 mg of oral nicotine will certainly not evoke the severe adverse effects described, such as clonic seizures and loss of consciousness."So either the dose was much higher than listed - 3mg/kg, not 3mg - or their chemical supplier screwed up and it wasn't nicotine. (Check date; credit goes to serendipity.) However, Mayer is not saying that those symptoms are unlike nicotine, instead explicitly saying they are like nicotine. (Wikipedia confirms.) It very strongly suggests the dosage unit was typoed.
The person who first dropped the units was Rudolf Kobert, who published in 1906, "in accordance with the severe symptoms evoked in several experimenters by 0.002–0.004 g it is certainly not going to be higher than 0.06 g." Explicitly guesswork.
That said, he was "a renowned pharmacologist" and thus no more likely to make bad guesses in his field than I am. Mayer's cautious lower limit for lethal dose is 1 gram, whereas Kobert said, if we assume the typo theory, that it certainly won't be above 2.5 grams for an average male of 1900. It's all consistent. Getting a mistake consistent doesn't happen by chance.
On the other hand Mayer needs to hang around engineers for a while. Check for small problems before assuming there's a big one. It's cheaper. While he was still helpful, having to steelman everyone gets tiresome after a while. Either learn logic properly or stick to reporting data and leave the interpretation up to an expert. I learned it and there's no reason Mayer couldn't too. In the worst case, the point for Mayer was to shame self-experimentation, not to show anything about nicotine.
Note about unmistakeable evidence - technically we must consider that Kobert didn't in fact observe seizures. All we know is that Kobert reported seizures. Or do we? We must, technically, doubt that we've seen the report. Names get typoed too, etc. Pragmatically, the chance is indistinguishable from zero. Pharmacologists don't think they've seen a seizure when they haven't, and if he'd tried to lie he would have been caught. Finally, that we know we think we've seen the report is not pragmatically like 100%, not even lim approaches 100%, it's plain 100% likely to be true.