154 IOWA DEPARTMENT OP AGRICULTURE 



herd where no cholera existed and no immediate danger of it in the 

 community. 



I could give you one instance for which I have the word of a breeder 

 of hogs who has carried the hlue away from Des Moines a number of 

 times. A neighbor came eight miles to see him, and started to go out 

 to see the hogs. This man said to him: "You had better not go into 

 hog barns; I have got cholera." He had given the simultaneous, and 

 the serum had not been up to full potency, and some had died as a re- 

 sult. "Oh," said the man, "I am not afraid of cholera; I use so-and-so 

 in the swill barrel; I have never had it and never expect to." They went 

 in. At the right time, cholera broke out in the visitor's herd and spread 

 to other herds. That was a secondary result from simultaneous treat- 

 ment. If the first man had been under proper quarantine, such as is in 

 vogue in Ohio, and should be in other states, the visitor would have been 

 forbidden to go into that barn, and he would not have started the out- 

 break on his own farm and the farms of his neighbors. 



I suppose you all knov/ how serum is made. The first step, supposing 

 that we have some serum and some viru:5 on hand, is to select an adult 

 hog, the bigger and stronger, the more resistance to cholera. That hog 

 is given a full inoculated dose of the strongest cholera virus, and with 

 it a full dose of potent serum. The result will be that he will be 

 immunized. He may or may not be sicl?:. As a rule, they are delicate 

 for about three days and miss their meals most of the time; but at 

 the end of ten days that hog is as well as ever, and is absolutely im- 

 mune to cholera. The reason we know he is immune is that the next 

 step in the process is to make a hyper-immune of him, and we give 

 him enough virus to kill a thousand hogs like him if they are sus- 

 ceptible to cholera, and he never misses a meal. Ten days after he gets 

 that big dose he is ready to bleed for serum. I should have said in the 

 start that he must be a hog with a long tail; we can't use the tail-less 

 hog for bleeders. Ten days after he is immunized we cut a piece off this 

 tail until we can get it to bleed. We put him in a crate and have a 

 clean sheet that covers the whole part, and the tail comes out in a 

 little hole in the sheet. The tail is shaved and disinfected and sponged 

 with alcohol, so that it is antiseptic and free from any germ infection; 

 and we bleed him into a covered vessel from the end of the tail. It will 

 bleed a few minutes and stop, and then by snapping against the tail 

 will start again. Some bleed every seven days; some every ten. You 

 bleed him what you think he can stand without getting weak. I 

 think probably the general rule is ten-day intervals. These hogs are 

 given a pretty good ration of feed. The Ohio laboratory has even of- 

 fered the balanced ration, which is all right. Our experience is that 

 you can't put them on full corn ration, or they will be too fat before you 

 get through bleeding them. After you have ble(^ him three times, if 

 you have lots of tail left (I don't know why it is that an audience laughs 

 at that!), you can re-hyper-immunize him. The theory is not properly 

 worked out yet as to what quantity you should give him in that re- 

 hyper-immunization. It is supposed from the experience that has been 

 had in the production of anti-toxins that each animal is probably only 



