PROPHYLACTIC TREATMENT OF HYDROPHOBIA 619 



certainly have caused a fatal result. He also elucidated the 

 fact that the exalted virus contained in the spinal cords of 

 rabbijs such as those referred to, could be attenuated so as no 

 longer to produce rabies in dogs by subcutaneous injection. 

 This was done by drying the cords in air over caustic potash (to 

 absorb the moisture), the diminution of virulence being propor- 

 tional to the length of time during which the cords were kept. 

 Accordingly, by taking a series of* such spinal cords kept for 

 various periods of time, he was supplied with a series of vaccines 

 of different strengths. Pasteur at once applied himself to find 

 whether the comparatively long period of incubation in man 

 could not be taken advantage of to " vaccinate " him against 

 the disease before its gravest manifestation took place. The 

 following is the record of the first case thus treated. The technique 

 was to rub up in a little sterile bouillon a small piece of the 

 cord used, and inject it under the skin by means of a hypodermic 

 syringe. The first injection was made with a very attenuated 

 virus, i.e., a cord fourteen days old. In subsequent injections 

 the strength of the virus was gradually increased, as shown in 

 the table : — 



July 7, 1885, 9 a.m., cord of June 23, i.e. 



10 

 11 

 12 

 13 

 14 

 15 

 16 



I P.M. 

 9 A.M. 

 6 P.M. 



11 a.m., cord of July 1 



25 

 27 

 29 



14 days old. 

 12 



11 



7 „ 5 



9 „ 4 



11 „ 3 



13 „ 2 



15 ,, 1 day old. 



The patient never manifested the slightest symptom of hydro- 

 phobia. Other similarly favourable results followed ; and this 

 prophylactic treatment of the disease quickly gained the con- 

 fidence of the scientific world, which it still retains. 



An important modification in the method which further experience led 

 Pasteur to make was in the treatment of serious cases, such as multiple 

 bites from wolves, extensive bites about the head, especially in children, 

 cases which come under treatment at a late period of the incubation 

 stage, and cases where the wounds have not cicatrised. In such cases 

 the stages of the treatment are condensed. Thus on the first day, say 

 at 11 a.m. and 4 p.m. and 9 p.m., cords of 12, 10, and 8 days respectively 

 are used ; on the second day, cords of 6, 4, and 2 days ; on the third 

 day, cords of 1 day ; on the fourth day, cords of 8, 6, and 4 days ; on 

 the fifth, cords of 3 and 2 days ; on the sixth, cords of 1 day ; and so on 

 for ten days. In each case the average dose is about 2 c.c. of the emulsion. 



