SUMMER DIARRHCKA I 59 



(/?) Bacteriological investigations. 



Up to the present the infective agent of summer diarrhoea 

 has not been identified with certainty. Different organisms have 

 been reported as being particularly prevalent in the faeces in 

 different epidemics in various localities. In America B. dysenteries 

 (Flexner type) has been encountered in the stools in some 

 epidemics [Wollstein (1903), Park, Collins and Goodwin (1903), 

 Duval and Schorer (1903), Cordes (1903) and Weaver, Tunni- 

 cliffe, Heineman and Michael (1905)], but not in others. 



Various other organisms, including B. enteritidis sporogenes, 

 B. enteritidis (Gaertner), B. vulgaris, have been regarded as the 

 causative agents in certain outbreaks. 



During the epidemics in London in the years 1905, 1906, 

 1907 and 1908 Morgan (1906, 1907), and Morgan and Ledingham 

 (1909) carried out extensive investigations on the non-lactose 

 fermenting and non-gelatin liquefying bacilli in the stools of 

 infants. A very large number of such organisms were isolated 

 and examined, but the only one whose prevalence was found to 

 be related to infantile diarrhoea was a non-motile bacillus of 

 this group, which fermented glucose with the production of gas, 

 but failed to ferment any of the other * sugars ' on which it was 

 tested. This is now generally known as " Morgan s No. i " 

 bacillus. This bacillus was frequently recovered from the organs 

 of fatal cases, and produced diarrhoea when fed to monkeys and 

 young rats. It was rarely met with in children not suffering from 

 acute diarrhoea. In 1905 this bacillus was found in the faeces of 

 54 Yo of acute diarrhoea cases, in 1906 in 56''/o, in 1907 in 16V0 

 and in 1908 in 53 7o- 



Since 1910 several investigations^ published in the 40th and 

 41st Annual Reports of the Medical Officer, have been carried out 

 for the Local Government Board. In the summer of 1910, when 

 epidemic diarrhoea was relatively uncommon, Lewis (191 1) 

 made observations in Birmingham, Ross (191 1) in Manchester, 

 Orr (191 1 ) in Shrewsbury and O'Brien (191 1) in London. Ross 

 and Orr found that non-lactose fermenting bacilli, which do not 



' The bacilli found in all these investigations are recorded in Table 23. 



