Described as the "Cadillac of Stethoscopes" this is also called a Cammann and is very rare. It is a Binaural scope, patented by G. P. Cammann in 1855. Considered to be the "Holy Grail" of stethoscopes by collectors, the only other seen in recent times was sold on E-Bay for nearly $3000.00.
In the late 1870s a variety of models introduced a center tension adjustment (i.e. Knight). This treasure has a screw tension adjustment very similar to the Knight model. C.K. Wilbur, MD and Elisabeth Bennion picture this in their book “Antique Medical Instruments”. At 16' long, it is stamped “Sharp & Smith, Chicago” on the center metal adjustment, this example is in excellent condition, including the silk woven tubes and Bakelite Bell.