MELICK 



as described above, is subdivided into small glass tubes. Each 

 tube is filled to about two-thirds its capacity and sealed. The 

 tubes are then placed in a refrigerating chamber maintained 

 at 1 8 C. and remain there until required for use. 



Antigens so preserved are serviceable for a period of at least 

 three years. Slight decrease in antigenic value does occur in 

 that time, but it is not of such degree as to impair seriously the 

 antigen as a reagent. 



