EXPERIMENT STATION REPORTS. 151 



REPORT OF THE BACTERIOLOGIST. 



Director R. S. Shaw : 



Sir — Tlie report of the Bacteriological Division of the Experiment 

 Station is herewith submitted in the form of individual papers by the 

 several workers. 



Mr. Robbins submits his work Avilh salt solution in the production 

 of hyi>erimmune serum for hog cholera. 



DATA ON HOG CHOLERA WORK — SALT SOLUTION EXPERIMENT. 



In connection with the manufacture of hog cholera serum during the 

 past 3'ear, an effort was put forth to reduce the cost of manufacture by 

 increasing the supjdy of virulent material that would prove efficient in 

 hyperimmunizing jiigs. In other words, it was our desire to utilize 

 the cholera pigs for vims other than Aims blood. 



In manufacturing semm by the regular Dorset-Niles subcutaneous 

 methods, the vims pigs are sacrificed merely for their blood and this 

 virus blood is sufficient only to hyperimmunize one pig of equal size 

 to the vims j)ig. Thus, we can readily see that to reduce cost of manu- 

 facturing serum by this method rests to a great extent on reducing cost 

 of virus that will prove efficient. 



ORIGIN OF EXPERIMENT. 



Taking up the idea put forth by Dr. R. A. Cj*aig of the Indiana Agri- 

 cultural Experiment Station of using salt solution as a vims when 

 passed through abdominal cavity of virus pigs, we have centered our 

 Avork upon this factor. It was our desire to detennine the value of this 

 saline solution as a virus and advance methods of using it, if possible, 

 that would prove ejfficient and practical. 



As far as I know of Dr. Craig's work along this line at the present 

 Avriting is the fact that he stated in Bulletin No. 140, issued February, 

 1010, that he used virulent salt solution to success in hyperimmuniziiig 

 animals and had secured potent serum from same. In the report of 

 Agricultural Experiment Stations, he states that virulent solution re- 

 moved from abdomen of vims pigs tAvo hours after injection had proven 

 successful in hyperimmunizing and produced potent sera. 



TECHNIQUE E:MPL0YED. 



Not having an accurate method of testing semm. keeping in mind that 

 the virulence of virus varies according to its source, that the potency 

 of serum varies according to virulence of A^rus used, amount of virus 

 injected, and condition of pig used for hyperimmune before and after 

 injecting, Ave found that it required numerous and careful experiments 

 to justify our results, each being run parallel Avith the Dorset-Niles sub- 

 cutaneous methods as a check. 



In these experiments I used .7.5% to .85% saline solution. The solu- 

 tion Avas sterilized and kept so in cotton-plugged flasks. Just before 

 using, it was heated to about 37i/^° C. It was injected at this tempera- 

 ture by means of a sterile aspirator apparatus, into abdomen of virus 

 pigs, in varying amounts and let remain A'^arious lengths of time so that 

 we might determine just Avhat time would prove more satisfactoiw and 

 the approximate amount to inject. This solution, or that part of it re- 



