CLINICAL EVIDENCE OF VALUE OF SERUM 463 



Many excellent men remain in the state service more on account 

 of their desire to do a public service to the people of their state, 

 rather than for the salary which they are able to obtain in the 

 employ of the state. 



However, it cannot be denied that there are a number of com- 

 mercial firms that are in the serum business merely for the money 

 there is to be made out of it, and they are willing to sacrifice 

 quality and purity of their serum in order to increase the percent- 

 age of profit and increase sales by making a cheaper priced serum. 

 Beware of the low-priced serum. Good serum cannot be made 

 and offered at a low price. This is one of the recognized draw- 

 backs in the manufacture of serum to-day, and both state and 

 private laboratories are straining every effort to devise a method 

 of growing virus outside the animal body for the purpose of 

 lowering the cost of the product. 



It is decidedly interesting to note, in connection with what 

 has already been said in previous pages of this work, the results 

 following single and double treatment in this herd. It will be 

 recalled that it has been repeatedly pointed out in the preceding 

 pages that the protection given by the single treatment was only 

 temporary, and that it was lost as soon as the effects of the serum 

 injected at that time had worn off. 



This single method of treatment does not educate the cells 

 of the animal body to manufacture antibodies, and without these 

 antibodies there can be no protection. On this account we are 

 not surprised to note in this herd that the small shoats and little 

 sucking pigs had lost their immunity or protection, and were 

 victims of the outbreak of cholera which did not occur for several 

 weeks after the serum had been given. 



This will practically always be found to be the case where the 

 single treatment is used. The protection is strong immediately 

 following the use of the serum, but it passes off in from three to 

 eight weeks, and the animal again becomes susceptible to the 

 disease unless retreated. 



The young pigs were given the single treatment in this case 

 because they were too young to use the double method to good 

 advantage. It will be remembered that the statement has already 

 been repeatedly made that the double treatment, when used in 



