20 



farmers' BULLETIN 834. 



Fig. 8. — Injection back of ear. 



the treatment has been completed. This marking is done visually by 

 placing a hog ring in the upper border of one ear. Hogs that are in 

 an advanced stage of the disease should, as already stated, be de- 

 stroyed ; if for any reason this is not done, they may be marked by 

 placing two rings in one ear or one in each ear. 



It is an injustice to the operator, to the owner of the herd, and to 

 the serum producer to administer serum to hogs without at the same 

 time taking and recording the temperatures. It is not uncommon 

 to find a herd which appears to be perfectly healthy, although a large 

 percentage of the hogs may have high temperatures. If such herds 

 are treated without knowledge of this condition, the owner may be 

 led unjustly to condemn the serum or the man who applied it, for 

 some losses are likely to occur, particularly if the operator is not 

 warned beforehand by the temperatures of the need for large doses 

 of serum. On the other hand, if the temperatures are taken the 

 operator knows whether to give an ordinary dose of serum for a 



