220 MEDICAL BACTERIOLOGY 



for a few minutes so that gross particles precipitate, then draw several cubic 

 centimeters into a glass syringe. 



Have an assistant hold a rabbit. With a sharp scalpel make an incision 

 about ^ inch long through the skin in the median line midway between the eyes. 

 Bore a small hole through the bone and thrust the tip of the needle through the 

 dura and inject several drops with the syringe. Seal the incision with collodion 

 and place rabbit in a closed observation cape. The period of incubation is 

 usually less than 3 weeks, occasionally it is prolonged. 



The onset of the disease may be marked by maniacal excitement followed in 

 24 to 72 hours by progressive paralysis and death. The stage of excitement may 

 not occur, the first evidence of the disease being paralysis of the hind quarters 

 and muscles of deglutition "dumb rabies" the paralysis progressing and 

 terminating fatally in 3 to 5 days. 



The specific cause of rabies is still a mooted point. Some believe the negri 

 bodies the specific cause (not likely). F. Proescher and others have isolated 

 from the brain and cord of rabid animals a small coccus which may or may not 

 be the cause. Probably not. 



The causative virus, whatever its nature, is present in the saliva and in the 

 spinal cord and brain of infected animals several days before the onset of the 

 disease. It resists antiformin and glycerin, and can be transmitted from animal 

 to animal. 



Pasteur discovered that after passing the virus from one rabbit to another 

 through a series of about 40 or 50 rabbits, the virus finally acquires certain new, 

 permanent properties and is then known as "Virus Fixe." 



Rabies vaccine is made from the spinal cord or brain, removed from a rabbit 

 dead from the effect of inoculation with virus fixe. 



The amount of virus in such brain or cord is attenuated by suspending it in 

 a glass jar over a layer of potassium hydrate at 22C. The longer it is so dried 

 the greater the attenuation, until the virus entirely disappears, which it will do 

 in from 3 to 4 weeks, according to the thickness of the cord. 



Pasteur's method of administering rabies vaccine to man is about as follows : 



Day of treatment Cord that has been dried, Amount 



days 



ist day, 10 A M. 14 or 13 3 



ist day, 4P.M. 120111 3 



2d day, 10 A.M. 10 or 6 3 



2d day, 4 P.M. 8 or 7 3 



3d day, 10 A.M. 6 2 



3d day, 4 P.M. 6 2 



4th day, 10 A.M. 5 2 



5th day, 10 A.M. 5 2 



6th day, 10 A.M. 4 2 



7th day, 10 A.M. 3 i 



8th day, 10 A.M. 4 2 



9th day, 10 A.M. 3 i 



loth day, 10 A.M. 5 2 



nth day, 10 A.M. 5 2 



1 2th day, 10 A.M. 4 2 



