MICROLITER DIVER TECHNIQUE 377 



(3) The divers to be used are heated (page 353). 



(4) Each diver receives 0.1 ix\. of sea water as "forerunner" (page 362) ; if 

 this does not satisfactorily moisten the inside wall of the diver an amount of 

 sea water sufficient for such moistening is introduced into the diver bulb and 

 sucked out again until 0.1 imI. is left (page 362). Until ready for use the divers 

 are kept in an atmosphere saturated with sea water. 



From this point on the description of the manipulations applies 

 to only one diver. 



(5) The centering of the pipettes (page 361) for sodium hydroxide, paraffin 

 oil, and air (for placing the mouth seal) is checked and the two former pipettes 

 are filled. Of these the sodium hydroxide pipette is filled last, and it is to be 

 borne in mind that a small portion of the contents evaporates during the period 

 before pipetting off. NaOH isotonic with sea water! (page 365). 



(6) Immediately before picking up the organism in the braking pipette (page 

 359) the diver is mounted in the clamp stand (page 357). 



(7) The organism is picked up, and the water which enters the pipette 

 along with it is either adjusted to the mark or its length is measured (page 

 361). 



(8) The braking pipette is mounted in its holder (page 361), the diver placed 

 under it, the centering checked, and the pipette is emptied into the forerunner. 



(9) The sodium hydroxide seal and the oil seal are placed in the diver neck 

 (page 365). 



If it is desired to check the contents of the diver under the microscope in 

 order to determine whether the organism has suffered by the pipetting it is 

 best done at this point, after the placing the oil seal. 



(10) The mouth seal is placed (page 366). 



(11) The diver is transferred to the thermostat, introduced into the flota- 

 tion vessel (page 374), and freed from any air bubbles that may stick to its 

 outside wall (page 374). 



(12) The diver mouth is rinsed (page 375). 



(13) The air bottle is shut against the outside air and manometer measure- 

 ments are started (page 375). Each measurement lasts about 3 minutes. 



(14) Upon completion of the manometric measurements the diver is re- 

 moved from the thermostat and rinsed, whereupon the condition of the organ- 

 ism is checked under the microscope, best by submerging the entire diver in 

 water. 



(15) The neck seals are removed, the diver neck rinsed (page 364) and the 

 organism removed from the diver (page 363). 



(16) The diver is cleaned (page 353). 

 (17 The diver is dried (page 353). 



It takes about 10-15 minutes to perform the manipulations 6-12. In a series 

 of experiments, therefore, this is the time interval between the initial ma- 

 nometer measurements of the two subsequent divers. 



