The uncertain results given by the visual types of hemoglobinometers have suggested the use of photoelectric apparatus for the determination. However, the photoelectric colorimeters have been too expensive for purchase by most physicians.
Our photoelectric hemoglobinometer is so designed that it can be manufactured for a price comparable to the cost of other hemoglobinometers and furthermore is simple and convenient to use. This is accomplished by using a small disposable celluloid cell for holding the diluted blood. This feature has resulted in an apparatus that can be constructed with the economies of modern molded plastics.
The operation of the hemoglobinometer can be seen by reference to the illustration. The disposable cell (1) is positioned in the light beam by a slot in the cell guide (2). The cone (3) which encloses the photo cell and filter has a small hole in its tip. This allows light from a restricted area
Dick GF, Stevens DS. A PHOTOELECTRIC HEMOGLOBINOMETER. JAMA. 1940;114(12):1065-1066. doi:10.1001/jama.1940.62810120001010