Beschreibung:

HELMHOLTZ, Hermann von (1821-1894). Autograph manuscript signed ("H. Helmholtz"), "Vorlafiger Bericht ber die Fortpflanzungsgeschwindigkeit der Nervenreizung". Knigsberg, [before 21 January 1850]. 2 pages, 4 o (110 x 30 mm), paper loss to right margin with loss to final few letters of nine lines, small tear to lower right margin, affecting 1 or 2 words of text. With two-line autograph note at top of page 1 by the physiologist Johannes Mller; autograph note signed at top right, by Johann Franz Encke, Secretary of the Berlin Academy. THE FINAL AUTOGRAPH MANUSCRIPT VERSION FOR PUBLICATION OF HELMHOLTZ'S CRUCIALLY IMPORTANT PAPER MEASURING THE ELAPSED TIME OF NERVE CONDUCTION. This was one of the most important papers in biophysics, and especially in electrophysiology, because it showed that nerve conduction could be measured. Until the eighteenth century, the concept of vital and animal spirits dominated theories of the sources of muscular movement. Galvani, following his experiments on frogs, argued that animal tissues generate electricity. In 1834 Johannes Mller finally dismissed theories based on animal spirits and suggested that the nervous impulse might be electrical on account of its speed, which he considered too rapid to be measured. It took another 16 years for his pupil Helmholtz to obtain such measurements. Once the timing of nerve conduction had been measured, then the velocity of the nervous impulse could be calculated, as Helmholtz reported in his paper of 1852. When Helmholtz reported these final results of his measurements in 1852, they showed that comparing animal electricity in a nerve with Voltaic electricity flowing along a conducting wire was a mistake. This manuscript was given by Helmholtz to Encke, Secretary of the Berlin Academy of Sciences, for presentation at the next meeting of the Academy. There is a small note by Encke in the upper right corner, signed and dated 21 January 1850, recording that the manuscript is for the January report of the Monatsbericht , of the Academy. Encke was the highly distinguished head of the Berlin Observatory and was influential in the development of modern astronomy in Germany. The manuscript then passed to Johannes Mller for publication in his Archiv fr Anatomie, Physiologie, und wissenschaftlichen Medicin , where it appeared in the 1850 volume (see lot 52). Mller crossed out Encke's note and added three lines after the title, giving the author's name and title and noting again the article's inclusion in the Monatsbericht . This manuscript is virtually identical to the printed version as it appeared in the Archiv .