THE DIALYSATION PROCESS I5 1 



not to spill any of the egg solution upon the exterior 

 of the dialysing tube. Should this occur, the dialy- 

 sate would incorrectly show a positive reaction for 

 peptones, when, for instance, the biuret test is 

 applied, since both albumens and peptones give this 

 reaction. To avoid any chance of such an error, the 

 dialysing tube, after having been filled, is closed at the 

 top between the thumb and forefinger and well rinsed 

 in running water. Then the tube is closed in the 

 same manner half way down, and water is allowed 



FIG. 7. 



to enter the upper part of the tube, so as to wash that 

 part of the dialysing tube which, during the dialysing 

 process, projects out of the dialysate and above the 

 layer of toluol. By moving the thumb and fore- 

 finger towards the upper end of the tube we expel 

 the water remaining after washing. All these manipu- 

 lations have the following object :- 



When filling the tube with albumen its interior, 

 near the free edge, rnav easilv come into contact 



fj / */ 



with the pipette. Some of the albumen may adhere 

 to the edge of the tube and dry up in time. At the 



