Stability of Antisera and Sera 125 



for reacting with their own antisera. Judging from the control 

 experiments with recently dried bloods we .should think that the period 

 between the addition of the antiserum and the formation of the cloud 

 was increased, and the magnitude of the cloud diminished. 



Fluid sera appear to deteriorate at any rate in some cases by 

 keeping. It has been occasionally observed, however, in qualitative 

 tests that old sera appear to react better than fresh ones." 



