53 
The little bulbs in which the serum is preserved, shown in hg. 8, 
are made of amber glass. The following method is used in hlling and 
sealing these bulbs: 
Cotton is first introduced in the neck as far as the constriction. 
Then about 1 gram of phosphoric anhydrid is placed in one of the 
bulbs. The neck through which the acid has entered the little 
apparatus is now sealed oti‘ by the blowpipe. Then about 1.2 grams 
of the dried serum are placed in the other bulb. The neck, from the 
f- 
Pig. y. — U-iihaped tubes used for preserving the standard serum. Exact size. 
r 
serum side, is connected with a vacuum apparatus, and as soon as the 
vacuum is sufficient!}" high this is also hermetically seah'd. 
Each bulb is now sealed in a black box, which excludes the light, 
and is kept in the ice box at 5° C., as l)efore stated. 
From this arrangement it will be seen tlnit the })owdered serum is 
kept dry, free from contact with the oxygen of the air, guarded 
against the action of light, and preserved at a constant low tempei’a- 
ture. 
