A new stopcock for pharmacological purposes

Summary

A stopcock for perfusion or superfusion with a very small dead space is described. It permits rapid switching from one of three pre-selectable solutions to another one of three pre-selectable solutions. The moving part of the stopcock contains two bore holes, one for each position of the main stopcock. When one solution is flowing through one bore hole to the preparation the other bore hole can be rinsed with the next preselected solution. This stopcock is normally used for superfusion of single Ranvier nodes but could serve many purpose in pharmacology.