A 1914 Portable Sphygmomanometer, designed by Percival Nicholson
This absolutely stunning example of American scientific ingenuity was designed by Percival Nicholson himself, one of the leading lights of American cardiology at the turn of the century. What Nicholson wanted to achieve was a device that would be, for the first time, a truly portable mercury-based blood pressure monitor.
The lid of the delicate mahogany box lifts to reveal a glass manometer that is folded in half. The manometer them extends with metal scale to 260 mm Hg. The reservoir is at the side of the scale. When the tube folds down a valve closes to prevent the loss of mercury. The inside base contains directions on an attached metal plate.
Technology was expensive at the turn of the century
According to an advertisement in the Journal of the American Medical Association, in 1915, this sphygmomanometer was sold for $15.00, which if translated to prices in 2018, would be a whopping $366.00.
Label inside bottom of mahogany case marked: "THE NICHOLSON 'PRINCO' SPHYGMOMANOMETER -- DIRECTIONS: PRECISION THERMOMETER AND INSTRUMENT CO. 1434 BRANDYWINE STREET, PHILADELPHIA, PA. -- PATENTED NOV. 4TH, 1913. APRIL 14TH, 1914. APRIL 28TH, 1914 -- OTHER PATENTS APPLIED FOR ALSO PATENTED IN FOREIGN COUNTRIES".
The first blood pressure monitors were cuffless...
What is interesting is that at the time (1914), the science of blood pressure cuffs was still very hazy. On the first blood pressure monitoring devices developed by Riva Rocci, Janeway, Spengler and others, the cuff was still a basic garrot. But the science of cuffs was in ebullition and it was Von Recklinghausen in Germany who, in a series of elegant experiments, demonstrated the importance of using the correct size cuffs and that there was a direct relation between accuracy and blood pressure cuff size. In 1914, when this device was created, most blood pressure monitors were still sold without a cuff and the doctor using the device would use whatever he had in hand at the time.
Sphygmomanometer : mahogany, glass, mercury, nickel-plated metal.
Dimensions: 3.9 x 17.6 x 5.8 cm
Discover the Percival Nicholson sphygmomanometer and other amazing blood pressure devices on www.bloodpressurehistory.com