| The specificity in the agar diffusion precipitation test of the reaction between the antigen of hog cholera virus diffusing from infected tissues and its homologous antibody was verified. Alternate freezing and thawing of infected tissues was found to give optimum release of the antigen from fresh tissue frozen for 18 hours. A study of the effect of the size and age of pigs upon the diffusion of the antigen from tissues showed that tissues from pigs of less than 250 lbs. gave good results provided the tissues were from animals showing gross clinical manifestations. Specimens from infected breeding sows and dead animals usually did not give a reaction. |
