706 INFECTION AND IMMUNITY. 



According to Harvey and McKendrick, the degree 

 of infectivity of dried rabic virus is a "function 

 of the loss of weight in water caused by the dry- 

 ing." 

 Technic of As is well known, the Pasteur prophylactic 



Treatment. 



treatment consists of the subcutaneous injection 

 on successive days, of suitable quantities of virus 

 fixe, prepared as described above, beginning with 

 the cord which has been desiccated for fourteen 

 days and gradually using fresher cords until viru- 

 lent virus has been inoculated. The vaccine is pre- 

 pared for use by emulsifying one centimeter of a 

 cord in 5 c.c. of salt solution or some "artificial 

 serum," and in a single treatment from 1 to 3 c.c. 

 of this emulsion is injected, usually into the sub- 

 cutaneous tissue of the anterior abdominal wall. 

 In this region there is less likelihood of injuring 

 large nerves, and local complications, which, how- 

 ever, occur rarely, are of less consequence. 



The rapidity with which one should pass from 

 the fourteen-day cord to fresh virus depends on the 

 urgency of the case. When there is good reason to 

 suspect a short incubation period, or when some 

 days have followed the bite an "intensive" treat- 

 ment should be used ; in other cases the progression 

 may be slower. The following conditions augur 

 a short incubation period: Bites of children, who 

 are more susceptible than adults, and in whom 

 the injuries usually are on the face; bites on the 

 face and neck in all cases; lacerated wounds in 

 which there is a larger surface for absorption of 

 the virus. The influence which proper cauteriza- 

 tion exerts on the incubation period was mentioned 

 above. 



