Pipet Bulb A simple and inrxpmsivc univrr*al pipt?t lrnll, nrade from ruhher tohing was described in a recent article in this Journal [Taturn, Charles M., Jr., 55,:iX (1!17X)I. In rewrmsu to t h a t article I offer an inexpensive pipet filler of my own design which need not he remwed from the pipet ;l* hlr.'Tatunt's nwdel. It consists of a 30-ml polyethylene dropping hottle and twa (2) 14-mm o.d. r u t h e r stoppers f n m rvacu:tltd blood s;implinz tuhes usually available from local hospitals without charge. I,he filler may be rnadu hy rut ling a h d r in the lrottom of the :in-ml bottle with a # 7 cork borer. Fit the 14-mm a d . stoppers in mouth and the hole uI' thv holtle just rot. 'The hottam of the hottle now serves as the top of the filler. T h e hole t o receive the pipet can Ilc mlrdr with s cork 1mrt.r si.,.rd t o fit the pipet used. T h e hole a t the top may he made with a small diameter drill bit (:fi6 in.).
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With the index finger i m the t w hole, *c,oewr the huttle and draw liquid into the pipet. When the pipet is full, allow air tu enter the h d t l e hy releasing the index finxer. Quickly reseal the bottle with your finger toretain the liquid in the pipet. If hlow out pipets are o 4 , st:;rl the t c q and squeeze the hottle t o completely empty the pipet. With very little practice I he pipet twlv I N a m t r d l d as if the filler werc nut present. The totid cost for this unit is between $0.21 and $0.25 each. In using thi* pipet f i l h s t ( i r t l a n d dr. Sr. High Sehcrd we find it superior to the ten dollar ($10) models we have heen using. C o r t l a n d Jr. ST.High School Valley View Drive Cortland, N e w York 1:lIl15
614 / Journal of Chemical Education
David J. Newton
