German gold doctor’s watch with jumping seconds Circa 1905

Gold lever watch in original box by A. Lange & Söhne
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A Glashütte doctor’s watch with independent stoppable jumping seconds mechanism seconde morte, circa 1905.
Sold on November 4, 1905, for 543 marks to E. Pröhl company in Halle – with original box, Lange & Söhne operating instructions, original certificate, and Lange extract from the archives. 
An 18 Carat pink gold, engine-turned, monogrammed case; with case design Lucia and gold dome. Signed enamel dial with Arabic Empire numerals, auxiliary seconds, and gold Louis XV hands. Signed, frosted, gilt 3/4 plate movement with applied seconde morte -mechanism, gold screw compensation balance, hand-engraved balance cock, index spring fine adjusting device, and gold lever and escape wheel.
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Diameter: 53 mm
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Weight: 113 g
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Signed: A. Lange & Söhne Glashütte B/Dresden
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Seconde Morte, Dead Seconds
A hand that jumps forward when the second has elapsed. Breguet used the expression seconde d’un coup or “sudden second”.
Generally, the jump of a hand is a distinctive feature of a quartz watch. In mechanical watchmaking, this “function” is a technical feat.