$20.00 – $85.00
Blood Pressure Manometer
2 patents – construction improvement for less breakage and better accuracy, second has a mercury reservoir and glass measuring tube.
First USA patent on the stethoscope – for a concealed noiseless spring that eliminated vibrations.
Mortar and Pestle
2 patents – 1 for the design of chair, 1 for the cup holder for spittoon.
Bausch and Lomb Microscope
First Bausch & Lomb microscope. Both witnessed the patent document. Print includes these signatures.
Ophthalmoscope (for examining eyes)
2 patents – 1 one for a new and improved version, 1 for a battery dry handle.
Phoropter (for eye testing)
Invented by Henry DeZeng, who also trademarked the word Phoropter – a word that is now used for visual testers.
Felix Hoffman's patent on his refinement of the formulation that Charles Frederic Gerhardt tried but gave up on.