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Biological Therapy 



After defibrination and the addition of a preservative the 

 blood thus obtained constitutes whole blood anti-hog-chol- 

 era serum. The custom most generally followed is to sub- 

 ject the animal to one, two or three tail bleedings at inter- 

 vals of seven days after which the animal is bled to death 

 and all of the bleedings from each animal mixed. It has 

 been conclusively proven that these various bleedings each 

 contain the same degree of potency. After all of the blood 

 from several hogs is mixed into a serial lot it is tested for 

 potency upon seven susceptible pigs. 



THE PREPARATION OF PITMAN-MOORE SERUM 



In the Pitman-Moore Biological Laboratories both 

 whole blood and clear anti-hog-cholera serum are produced 

 under the same ideal conditions as described under the pro- 

 duction of hog-cholera virus. Every effort and precaution 

 known to science is utilized in producing this product to 

 maintain in it the highest possible potency and to insure its 

 freedom from any pathogenic bacteria, toxins or aggressins. 

 The purity of each serial lot of serum is determined by tests 

 which are distinctive and which are in excess of the require- 

 ments of the U. S. Government. Each lot is subjected to 

 most rigid bacteriological and microscopical examinations 

 to determine the freedom from pathogenic bacteria, while 

 the absence of toxins and aggressins is determined by the 

 injection of white mice and rabbits, both of which are par- 

 ticularly susceptible to these substances. 



THE PRODUCTION OF CLEAR ANTI-HOG-CHOLERA 



SERUM 



Several different methods are used for producing this 

 product which results in considerable variation in the ap- 

 pearance of the finished product. The essential point uti- 

 lized in all methods is the removal of the red blood corpus- 

 cles, after which the product is heated, phenolized and tested 

 for potency. Two varieties of clear serum are available. 

 These are known as concentrated and unconcentrated. The 

 difference lies in the amount of true serum contained in 

 each since it is necessary to add dilutents to both while pro- 

 cessing. Concentrated serum contains 80% true serum while 

 unconcentrated contains 65% which is equivalent to that 

 contained in whole blood. Although the true serum con- 

 tent differs, the amount of true serum actually injected into 



