98 VARIATIONS IN PATHOGENICITY [ch. vii 



anthrax bacillus and it did not revert after daily subculture 

 for two months afterwards. 



3. In the third place, a contagious disease passed from 

 one case to another during the course of an epidemic may he 

 characterised in different cases hy wid(^ different symptoms. 



Andrewes and Herder (1906) have recorded an example 

 of this. A woman (A), admitted for her confinement to a 

 maternity home, was attended by a nurse (B) who developed 

 tonsilitis on the day the patient was delivered, and three 

 days later was notified as a case of scarlet fever. The woman 

 (A) developed puerperal fever and was removed to a hospital 

 where she died. Three days after her death a nurse (C) who 

 had attended her at the hospital developed scarlet fever. At 

 the maternity home another nurse (D) took nurse B's place 

 and had attended the woman (A) for a day or two before the 

 latter's removal to hospital. Ten days later this nurse (D), 

 who herself remained well, attended another confinement case 

 (E) in the district. The woman (E) died of septicaemia on 

 the fifth day after delivery. Nurse B's room, having been 

 disinfected by the Sanitary Authority, was scrubbed by a 

 charwoman (F). On the following day this charwoman became 

 ill but the case was not recognised to be scarlet fever until a 

 day or two later when her two children (G) and (H) developed 

 typical scarlet fever and all three were removed to a fever 

 hospital. A scheme will make the sequence of events clearer : 



* Child (G) 

 Maternity nurse (B) Charwoman (F) / SearUtfeeer 



Scarlet fever *" Scarlet fever \ 



\ 



Child (H) 

 Scarlet fever 



Patient (A) Maternity nurse (D) — >- District case (B) 



Puerperal fever well 



Hospital nurse (C) 

 Scarlet fever 



The original case of scarlet fever infected two other people, 

 one with scarlet fever and the other with puerperal fever ; 

 this case of puerperal fever also infected two other people, 

 one with puerperal fever and the other with scarlet fever. 



An even more remarkable instance is recorded by Dunn 



