SUMMARY 509 



simultaneous treatment. If real virus is injected with a poor grade 

 serum a large number of funerals are bound to follow, and confidence 

 in the serum treatment is destroyed, when, as a matter of fact, the 

 trouble is not with the serum, but with the kind of serum used. 

 Make certain that the serum you buy has been really tested against 

 virus or else do not use it except for single treatment. 



SUMMARY 



In making a survey of these forty-seven cHnical reports on the 

 use of serum we must reach the following conclusions: 



(1) Hog-cholera serum is in itself a harmless substance, and 

 may be freely injected into well or sick animals without producing 

 any bad results. 



(2) The injection of serum in sufficiently large dosage in a 

 herd that has been exposed to cholera, but has shown no symp- 

 toms of the disease, will give them a protection against the disease 

 for a time. 



(3) This protection given by the serum-alone injection is only 

 temporary in character, and the animals may again take hog- 

 cholera if exposed several weeks later. 



(4) Hog-cholera serum, used in larger doses in herds where 

 the disease already exists, will often save a large number of the 

 animals, even saving many that are visibly sick at the time treat- 

 ment is given. The sooner after the start of the outbreak that 

 serum is used, the greater will be the percentage of hogs saved. 

 Every hour's delay means an increase in the losses. 



(5) Injections of 1 to 2 c.c. of virus may be made in a 

 healthy animal without producing disease if a corresponding dose 

 of serum is injected at the same time. 



(6) The injection of this double dose of serum and virus not 

 only will not produce disease, but it will result in the development 

 of a permanent protective power against invasion by cholera 

 germs. This is in contrast with the temporary nature of the pro- 

 tection resulting from use of the single method. 



(7) The animals which have been protected by the double 

 injection method may be afterward taken to cholera-infected farms 

 and placed in diseased feed lots, or with sick hogs, and they will 

 remain well and thrifty. 



