732 PASSIVE IMMUNIZATION SERUM THERAPY 



infection in a given case, good results cannot be expected. Probably 

 if some means were discovered for making a prompt bacteriologic diag- 

 nosis, and if several immune serums were on hand for the treatment of 

 infections caused by the main types, after the methods worked out by 

 Neufeld, Dochez, and Cole in the treatment of pneumonia, good results 

 may be obtained. 



The curative effect of dysentery antitoxin is shown by a reduction in 

 the number of stools, by the fact that blood and pus disappear from the 

 discharges, pain and tenesmus are relieved, the temperature becomes 

 normal, and the patient gains in weight. Individual observers are fre- 

 quently enthusiastic over the results obtained in individual cases, and 

 no doubt these are striking in those instances where the antiserum ap- 

 pears to be specific for the particular form of infection. 



THE SERUM TREATMENT OF HOG CHOLERA 

 While the cause of hog cholera has not as yet been discovered, it is a 

 well-known fact that the virus is present in the blood of infected animals, 

 and it is possible, by immunizing healthy hogs with gradually increasing 

 doses of infected blood, to prepare a potent immune serum that will 

 prove of value in the prophylaxis and cure of hog cholera. The nature 

 of this serum is unknown. It possesses many of the features of an anti- 

 toxin, and for the present may be classed with these. 



Production and Standardization of Hog Cholera Serum. Healthy hogs weigh- 

 ing about 100 pounds are selected, and injected subcutaneously with 40 c.c. of 

 hog cholera serum per hundred pounds of weight. Two or three days following 

 this protecting dose they are injected intravenously with 3 or 4 c.c. of sterile, defibrin- 

 ated blood, ob tamed from an animal suffering from the disease; or the animals 

 may be exposed in pens known to be infected. If the animals live for one month 

 without showing evidences of toxemia, they receive another injection of 5 c.c. of 

 infected blood (virus). Two or three weeks later they receive another injection of 

 from 15 to 20 c.c. of infected blood; in from fifteen to twenty-one days after this 

 inoculation they receive a final injection of from 4 to 5 c.c. of virus per pound of 

 body weight. Animals tolerating the last injection are said to be hyperimmune, and 

 are bled in ten days. In hyperimmunizing the animal some prefer to inject the virus 

 intraperitoneally instead of intravenously. If this method is adopted, about double 

 the dose of infected blood (virus) is required. About 5 per cent, of animals 

 succumb during the period of immunization. 



The immunized hogs are bled aseptically from the tail by snipping off the tip, 

 and 5 c.c. of blood per pound of weight is collected in sterile vessels. Each animal is 

 bled once a week until three or four bleedings have been made. 



In about one week after the last bleeding they are hyperimmunized again by 

 giving them 4 or 5 c.c. of infected blood per pound of body weight, and additional 

 bleedings are made so long as the tail lasts. 



