MICROLITER DIVER TECHNIQUE 373 



The gas is saturated with water vapor of the proper tension by- 

 passing through wash bottles of salt solution. The flow of gas 

 through C and D is controlled by pinchcocks, and bubble counters 

 are inserted. The gas stream through C is regulated to about one 

 bubble per second, and through D to about 2-3 bubbles per second. 



The manipulations are carried out as follows: 



1. Place the bottom drop in the diver before placing the diver in 

 the anaerobic filling apparatus. 



2. Bring the diver into the apparatus and allow 5 min. for the 

 gas in the diver to become equalized with that in the chamber (K) . 



3. During the latter part of the 5 minute period, bring the tip of 

 C into the bulb of the diver and allow the gas stream to flush 

 through the diver about 15 seconds. 



4. Place the neck seals while the diver is in the apparatus, and 

 the mouth seal after the diver has been removed from the apparatus. 

 The diver is now ready for measurement. 



In cases in which the exclusion of air is particularly important, 

 as in experiments on anaerobic metabolism of tissue having a low 

 oxygen consumption, place a drop of the diluted medium into the 

 mouth of the diver under anaerobic conditions using an extra 

 pipette for the purpose; this pipette need not be calibrated in any 

 way. Then remove the diver from the apparatus and draw the mouth 

 seal down into the neck by means of an "air pipette" (page 366) 

 as follows: 



(a) To prevent air from getting into the diver, pass the gas 

 through the "air pipette" until the moment the pipette is to be used. 



(6) The instant the "air pipette" is disconnected from the gas, 

 connect it to the tube which the operator holds in his mouth and 

 lower the tip of the pipette into the mouth seal. (A three-way stop- 

 cock connecting the air pipette with either the gas or the operator's 

 mouth facilitates the operation.) 



(c) Blow down the liquid which rises in the pipette by capillar- 

 ity until the tip is completely, or almost completely, emptied. Then 

 pierce the lower meniscus of the seal with the tip and extend it into 

 the gas space under the seal. 



(d) Suck out gas until the seal has been lowered to the desired 

 position, 



(e) Withdraw the pipette and rinse it at once to prevent clogging 

 by evaporation and crystallization. 



