JF Ptak Science Books Quick Post
Here’s another happy and unexpected find, this coming from one of my very-early-on scientific heroes, Hermann von Helmholtz. The two papers1 in question (French translations that appeared in 1850 and 1851 about a year after the results were published in German) form an interesting chapter in the history of infinity—in this case, closing the boundaries of speed of the neural impulses. As with the speed of light (thought to be infinite or thereabouts into the 17th century) the speed of “thought’ or “pre-thought” was thought to be infinite until this paper by the polymathic von Helmholtz. Von H worked in many different fields and made major contributions across numerous disciplines—he was a very very impressive guy, and evidently a good teacher, and also of fine character (as seen in the 2nd law business with Mayer). In this paper he was able to determine the speed of the nerve impulse in a frog, using its sciatic nerve and the calf it was connected to, and elegantly finding a speed of between 24-38 metres/sec., and presented in these two papers for the first time in French. The experiment was fairly simple and just remarkable, and presented the speed of the neural impulse at very much not light speed. And so, the infinity of the speed of thought—thought perhaps so because of religious demands—definitely had a bookend.
Notes.
1. Hermann von Helmholtz. “Note sur la vitesse de propagation de l’agent nerveux dans les nerfs rachidiens.” Published in Comptes Rendus vol 30, 25 February 1850, pp. 204-6; and “Deuxieme Note surla vitesse de propagation de l’agentnerveux”, again in .Comptes Rendus, vol 33, 1851 in pp. 262-5.