Immunization 75 



II. Protective inoculation with immune serum and cultures 

 (Simultaneous method of Lorenz and of Leelainche; sero- 

 yaccination). Blood serum of animals which have been highly 

 immunized by repeated subcutaneous or intravenous injections 

 of living cultures of the erysipelas bacillus will protect healthy 

 animals for a short time against fatal infection. The passive 

 immunity produced in this manner may be changed into active 

 immunity by simultaneous or subsequent injections of virulent 

 cultures of the bacilli. 



After Emmerich and Mastbaum (1891) found that the blood serum 

 of rabbits which had been immunized against erysipelas possessed im- 

 munizing properties, Lorenz (1893) produced an effective serum from 

 artificially immunized hogs. This serum, concentrated to one-third of 

 its original volume, was effective for protective inoculation of hogs. 

 As hogs as well as sheep (Voges) produce only small quantities of serum, 

 Leelainche (1898) and Schiitz & Voges hyperimmunized horses for that 

 purpose, and at the present time serum for the inoculation of hogs is 

 obtained almost exclusively from these latter animals. Potent blood 

 serum may also be prepared from cattle (Schreiber, Kitt), and the 

 "double serum" of Landsberger consists of a mixture of horse and 

 cattle immune serum (Schubert). 



The results of protective inoculations with immune serum 

 and bacilli culture have generally given good satisfaction in 

 practice. Hogs which have not yet become infected withstand 

 the vaccination as a rule without marked reaction, and they will 

 later resist natural infection. As a sequel of the vaccination, 

 however, urticaria, swelling at the point of inoculation extend- 

 ing to the throat, stiffness of the joints, occasionally erysipe- 

 latous endocarditis, and even death after 36 hours from severe 

 toxic action, have been observed to follow injections of the 

 culture. The advantage of this method over Pasteur's consists 

 in the development of the passive immunity immediately after 

 the serum injection, which condition in case of immediate dan- 

 ger of infection is of great importance — and further it is well 

 tolerated even by breeds of hogs with low resistance. The some- 

 what high cost of the vaccinating material is a disadvantage. 



Latent diseased processes are unfavorably influenced by the inocula- 

 tion. Thus, it was repeatedly observed in Germany that chronic pneu- 

 monia of pigs (the so-called chronic swine plague of pigs) became aggra- 

 vated after vaccination, and in Hungary also it was noticed that the 

 first year after the appearance of hog cholera severe outbreaks of the 

 latter disease developed following the vaccination of herds against 

 erysipelas. 



In Prussia 217,376 hogs were vaccinated in the years 1897-1899 by Lorenz 's 

 method, and after the first injection 0.018%, after the second 0.042%, later in the 

 course of the year 0.058% died as a result of erysipelas (Joest & Heifer). In 

 Baden 102,448 hogs were vaccinated in the years 1899-1906 of which 21,466 animals 

 received the serum alone; of these 116 (0.09%) died inside of 3 days, later until 

 the close of the year, 108 (0.08%) succumbed. In Hessen only 2 out of 35,258 in- 

 oculated animals died in the period from 1901 to 1908 (Lorenz). In Wurttemberg 



