CHEMICAL SELECTION OF MOTHERS. 



lor 



low. By smearing a little vaseline over the surface of 

 the rubber, one obtains a perfect joint; furthermore, it 

 prevents adherence of the liquid to its surface. It is 

 desirable to leave the capsule with its contents in 



Fio. 41. Detail of pipette, 



repose for a few minutes, to make sure that the diffu- 

 sion is complete. 



The method may be still further simplified by 

 doing away with flask M, and having the subacetate 



