CAPILLARY BULB PIPETTES 13 



Schrup suspends his cultures and thermometer in the water by threads attached 

 to pins in the cork of the vacuum bottle. The plug should be paraffined or covered 

 with a rubber cap. As regards the matter of a low-temperature incubator (for 

 gelatin work), this is best met by using a small refrigerator. The ice in the upper 

 part maintains an even cold, and by connecting up an electric lamp in the lower part 

 of the refrigerator we can easily maintain a temperature which only varies one or 

 two degrees during the twenty-four hours. 



With a i6-candle-power lamp a temperature of about 25 C. is maintained (this 

 is too high, being about the melting-point of gelatin) ; with an 8-candle-power, one 



10. 



FIG. 6. i, 2, 3, Drawing out glass tubing; 4, 5, Wright's rubber bulb capillary 

 pipettes showing grease pencil mark for making dilutions; 6, 7, Wright's U-tubes; 

 8, 9, 10, methods of drawing out test-tubes for vaccines in opsonic work; n, bac- 

 teriological pipette. 



about 21 to 23 C. ; and with a 4-candle-power, from 18 to 20 C. ; the box being 

 about 20X30X36 inches. 



When much serum reaction work is done, an electrically run centrifuge is a great 

 convenience. 



A filter pump attached to the water faucet, preferably by screw threads, is 

 almost indispensable for filtering cultures, etc., and for cleaning small pipettes, 

 especially the hsemocytometer pipettes. Such a filter or vacuum pump with a 

 vacuum gauge is more easily controlled. 



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

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



