HOG CHOLERA AND SERUM 91 



is given sufficient of a five per cent solution of carbolic acid so that 

 ultimately it contains one-half of one per cent of carbolic acid, this being 

 for the purpose of increasing its keeping qualities. 



This bleeding process is repeated at least twice at intervals a week 

 apart, the whole being then mixed to give a uniformity of product. It 

 should then be tested by practical experiment to determine its potency 

 before being sent out and is then ready for use. If properly prepared, 

 the serum is undoubtedly effective in immunizing against cholera when 

 used in doses of 20 to 25 CC for hogs weighing 100 pounds, with doses of 

 15 CC extra for each successive 100 pounds of live weight of hog. 



In warding off or preventing cholera by use of serum one of two methods 

 may be employed. First, by the injection of serum alone under the skin or 

 into the muscles of the animal. This is known as the simple serum method 

 and gives only temporary immunity, say for about thirty days. The sec- 

 ond method, known as the simultaneous method, consists in the injection 

 of the same amount of serum, but at the same time a small amount of 

 cholera virus, from 1 to 2 CC, according to the age and size of the 

 animal, is also injected into the animal being treated. The second method 

 produces what is known as active immunity, and is permanent in its char- 

 acter, lasting during the period of the animal's life. 



Which ever method is employed certain essentials must be absolutely 

 insisted upon if any degree of success is to follow the work; and 

 particularly in the simultaneous method must this be so if disastrous 

 results are to be avoided. 



Essentials. First, the serum and virus used must be pure and potent; 

 and second, the person treating the hogs must know his business thor- 

 oughly that is, he must be able to k-noio hog cholera when he sees it, 

 he must know which method to employ under the given or existing con- 

 ditions, and he must understand how to do the work. Failure in the 

 observation of these requirements will explain why there are still so 

 many breeders and farmers who doubt or question the efficacy of the 

 serum treatment and hesitate in its use. 



To secure the proper kind of serum and virus it is necessary that 

 all serum and virus should be tested to determine their potency before 

 they are sent out for use, and this by expert supervision under state or 

 federal control. Ample means and equipment for their manufacture should 

 be provided so that when emergencies arise and the demand for serum 

 and virus becomes large and urgent the calls could be met and the product 

 sent out would be pure and potent. This comes within the business of the 

 state. To be sure there are numerous commercial plants manufacturing 

 serum and virus, but these likewise should be brought under state or 

 national supervision to insure the excellence of their product. 



That the work of treating hogs should be done by one thoroughly ac- 

 quainted with the disease and competent to give the treatment should go 

 without saying, when one considers the importance of the undertaking and 

 the magnitude of the losses that may result if failure follows. 



Which Method? Which method of treatment should be used must be 

 determined by existing conditions. Where an outbreak has already occurred 

 and it is desired to treat the remaining apparently well animals the simple 

 serum method should be employed, for it is very probable that many, 

 if not all, of the animals so injected have become previously infected and 

 the treatment will result in permanent or active immunity. The use of 

 cholera virus on hogs that have already become infected or are other- 

 wise diseased is simply adding to their troubles and will almost invariably 

 result in the death of the animal. Further, the simple serum method only 

 should be used in treating brood soics in pregnancy, even though the treat- 

 ment may have to be repeated to carry them on through farrowing and 

 until their pigs are old enough to wean, and then both sows and piga 

 should be given the simultaneous treatment. 



The simultaneous method should always be used where permanent 

 immunity is desired, and especially so whenever the animals are to be 

 placed in lots or houses in which cholera outbreaks have previously 

 occurred. 



