The accompanying illustration shows a simple little instrument that I have found very satisfactory and accurate in filling blood pipettes. The apparatus consists essentially of a blood pipette from a Thoma-Zeiss hemocytometer and the ordinary metal barrel and plunger of a hypodermatic syringe, supplied with a pinion. The pinion was made and attached to the syringe by a local jeweler. To the pipette A is comented the metal ferrule B, into which screws the syringe C. The plunger of the syringe is operated by the pinion head E working in the notched piston shaft D.
In filling the pipette the instrument is held by the third and fourth fingers, the thumb and index finger of the same hand operating the plunger by means