SERUM THERAPY 287 



emulsion by pounding and extracting the muscles and organs, and obtained 

 a product which after filtration possessed both vaccinating and therapeutic 

 properties. 



(ii) Lorenz prepares a serum which has distinct therapeutic properties. 

 A rabbit is inoculated sub-cutaneously first of all with a few cubic centi- 

 metres of specific serum (1 c.c. per 1 kg. of body weight) ; two days later, 

 and again on the twelfth day, the rabbit is inoculated (sub-cutaneously) with 

 a virulent culture, the second and third doses being larger than the first. 

 After a further interval of 10 days a large dose of culture is administered 

 intra-venously. 



(iii) Mesnil, adopting Pasteur's method of attenuated viruses, immunizes 

 rabbits as follows : At intervals of 1 week a rabbit receives, first, O25 c.c., 

 then 1 c.c. of a very attenuated virus the first vaccine. This is followed 

 by inoculations of a less attenuated virus the second vaccine in doses of 

 O25 c.c. first and 1 c.c. later. Finally, at periods varying from a week to a 

 month increasing doses of virulent culture O25 c.c., 1 c.c., 3 c.c., 4 c.c., 

 5 c.c., 10 c.c. are used. Immunization requires about 6 months' treatment, 

 and in spite of the small doses used some of the animals die. It is only after 

 about 3 months that the animals under experiment can resist the inoculation 

 of a large dose of culture every week or 10 days without showing considerable 

 reaction. The serum of animals prepared in this way if given in doses of 

 0'05 c.c. protects mice against an inoculation of a virulent virus given the 

 following day. In doses of 0'25 c.c. it exhibits therapeutic properties provided 

 it be administered within 24 hours of infection. The serum is also efficient 

 in the case of pigeons and rabbits. It is not bactericidal, for if the bacillus 

 be sown in the serum it grows in long chains and moreover retains its 

 virulence. 



(iv) Leclainche uses horses for the preparation of his prophylactic serum : 

 200 c.c. of a virulent culture (one which will kill pigeons in doses of 0'25 c.c. 

 when inoculated into the pectoral muscle) are inoculated into the jugular 

 vein and the inoculations repeated at intervals of about 10 days. The 

 resulting serum is prophylactic for rabbits in doses of 0*5-1 c.c. and the 

 immunity conferred lasts 1 or 2 days. Inoculation of 1 c.c. of this serum 

 mixed with an equal volume of a virulent culture confers a lasting immunity 

 (Sera-vaccination) . 



Leclainche has applied this method to the vaccination of swine. He inoculates 

 healthy pigs on the inner side of the thigh first with a mixture of 5-10 c.c. of serum 

 and one-half a virulent culture, and 12 days later with one-half a virulent culture 

 without serum. If he has to deal with an herd already infected he inoculates them 

 with 10-20 c.c. of serum without any culture 2 days before he inoculates the first 

 vaccine. 



The serum has no appreciable therapeutic property. 



4. Agglutination. 



The serums prepared by Mesnil's and by Leclainche's methods agglutinate 

 the bacillus of swine erysipelas to a marked degree. The serums of infected 

 rabbits and pigeons show no agglutinating properties (Overbeck). 



SECTION IV. THE DETECTION, ISOLATION AND IDENTIFICATION 

 OF THE ORGANISM. 



The recognition of the disease is of supreme importance from the point of 

 view of vaccination, and the demonstration of the organism is of great 



