Having had occasion recently to make a large number of blood counts, I became impressed not only with the necessity of shaking the pipet thoroughly in order to obtain accurate results, but also with the time and exertion required to shake by hand. I accordingly devised an electric shaker.
The gong and ball of the hammer were removed from an ordinary electric bell, and a small spring clip, such as is used for hanging up negatives, was soldered to the end of the striker arm. The jaws of the clip were bent so as to hold a pipet securely, and it was placed in line with the long axis of the bell, but at an angle of 45 degrees with it, by bending the striker. Such an apparatus may be screwed to the laboratory table and operated by two dry cells with a switch in circuit; or it may be