Bouillon for formal dinners must be strained through a fine sieve and napkin and also be clarified as follows. Beat a raw egg white and add it to the boiling bouillon. When the egg has thoroughly boiled, strain the soup through a hair sieve, or still better, through a napkin that has been washed without soap. The napkin should first be moistened in cold water, squeezed out, and tied to an overturned stool. [Place a pan under the napkin to collect the strained bouillon.]
If the bouillon must be clear as crystal, strain it a second time, lining the napkin with white blotting paper.