GENERAL CONSIDERATION OF FILTRABLE VIRUS 



907 



of his own infection had elapsed. Pasteur successfully proved the 

 efficacy of his method upon dogs and finally upon human beings, the 

 first human case being that of a nine-year-old child Joseph Meister. 

 TECHNIQUE OF RABIES THERAPY. The technique developed by Pas- 

 teur is still, in the main, followed by those who treat rabies to-day. 



I. As a preliminary, it is necessary to prepare or obtain virus fixe. 

 This may generally be procured from an established laboratory or 

 may be prepared independently by passing street virus through a 

 series of young rabbits (weighing from 700 to 1,000 gms.). According 

 to Hogyes, 30 the passage of the virus through twenty-one to thirty 

 rabbits, in this way, will reduce its incubation time 



to seven or eight days. Babes claims to obtain a virus 

 fixe more rapidly by passing the virus alternately 

 through rabbits and guinea-pigs. 



For purposes of inoculation, virus is prepared by 

 emulsifying in sterile salt solution pieces of the 

 medulla or cerebellum of animals dead of a previous 

 inoculation. The brain tissue which is not emulsified 

 may be preserved under sterile glycerin in a dark and 

 cool place for further use. 



II. Rabbits are inoculated with virus fixe by in- 

 tracranial injection. A small incision is made in the 

 shaved scalp in the median line, and the skin is 



SPINAL CORD OF 

 RABBIT FOR 

 PURPOSES OF 

 ATTENUATION. 



retracted. With a small trephine or a round chisel, FIG. 100. 



an opening is made in the skull and in the angle OD OF DRYING 



between the coronary and sagittal sutures. Through 



this opening about 0.2 to 0.3 c.c. of the virus fixe is 



injected, either directly into the brain substance or 



simply under the dura. 



As soon as a rabbit so inoculated has died it is autopsied. The 

 animal before dissection should be washed in a disinfectant solution 

 lysol or carbolic acid. The skin is then removed and the animal, 

 lying on its ventral surface, is fastened to a dissecting board. The 

 spinal canal is then laid open with a pair of curved scissors and 

 the spinal cord carefully removed. This is accomplished by cutting 

 across the cord in the lumbar region, and lifting this with a forceps 

 while the nerve roots are divided from below upward. 



Tlic cord is suspended by a sterile thread within a large bottle 



* Hogyes, quoted from Kraus and Levaditi, "Handb., " etc., I. 



