PIPETTES 17 



a vacuum gauge is more easily controlled. In washing red cells in Wassermann 

 reactions a pipette attached to the rubber tubing of the pump facilitates the removal 

 of the supernatant fluid. 



The filter pump is indispensable when using the various types of porcelain or 

 Berkefeld filters. The Punkal or Muencke types of filter are the most convenient 

 in filtering toxins or in the sterilization of certain media when heating would be 

 unadvisable. 



-L-AVERY- 



FIG. 8. i, Apparatus combining various methods for culture of anaerobes; (a) 

 Hofmann clamp for connecting with vacuum pump; (6) pyrogallic at bottom of 

 bottle for Buchner's O absorption method; (c) deep glucose agar stab covered with 

 sterile liquid petrolatum (see anaerobes). 2, One-fourth inch capillary loop U tube 

 for making two nitric acid albumin tests (see chemical examination of urine). 3, 

 Piece of tubing bent to hold slide for steaming smears in flame. 4, Schmidt's fer- 

 mentation apparatus, as modified by using graduated cylinder (see under faeces). 

 5, One-fourth inch glass tubing, 4^ inches long with ^corks at each end. For 

 centrifuging faeces for ova. 6a, Apparatus connected with sterile centrifuge tube 

 for taking blood from vein of man or a guinea-pig or rabbit's heart. 6b, Erlenmeyer 

 flask which can be used instead of centrifuge tube. See under sections Immunity 

 and Blood. 7, A graduated pipette with Hofmann clamp applied to rubber bulb 

 for precise delivery of measured quantities of liquids. 



Capillary Pipettes. With the possible exception of the platinum 

 loop, there is no piece of apparatus so applicable to many uses as the 

 capillary pipette made from a piece of glass tubing. 



These may be made in a great variety of shapes. The one with a hooked end, the 

 Wright tube, is the best apparatus for securing blood for serum tests. The crook 

 hangs on the centrifuge guard and by filing and breaking the thicker part of the tube 

 2 



