Sir, - How did Yeats hypnotise hens? (In Time's Eye, November 13th). Well, he certainly didn't need to draw on any mystical doctrine. The practice of immobilising fowl and other small animals was widely practised, by peasants who found it a convenient way to transport livestock to market.
There are various procedures, such as holding the hen's beak against a line drawn on the ground and drawing the hen along the line, or suddenly inverting the held bird. The result can be a type of catalepsy, in which the animal remains rigid and unmoving for a considerable time. An allied phenomenon is to be seen in the way in which stoats are said to fascinate rabbits into a state of immobility by performing a complicated dance before their bewildered eyes. I wonder if any, of your readers has witnessed this?
Stage hypnotists often demonstrate rigidity of their subject's limbs or entire body, but this occurs only in response to verbal suggestions and not as a necessary consequence of the hypnotic induction procedure. However, it is still not clear how much human and animal hypnosis have in common fixity of attention and monotonous stimulation seem to be effective hypnotising requirements for many species, but I have never come across reports of animals responding to spoken commands when "entranced".
Yours, etc.,
Trinity College,
Dublin 2.