138 Proceedings of Royal Society of Edinburgh. [sess. 
to a reduction of 91*7 per cent, in the attacks in favour of the 
inoculated. 
The fact that twenty-one of the inhabitants were away at work 
all day, and only returned to the chawl to sleep at night, makes 
no difference between the two groups, for on enquiry it was found 
that no cases of plague had occurred in the various places where 
these people worked. The infection was undoubtedly localised 
in the chawl, and no circumstance existed that in any way favoured 
the one group over the other. The following statement brings this 
out clearly : — 
Of those going out to work during the day, 16 not inoculated 
had 10 cases. 
Of those staying at home all day, 16 not inoculated had 9 cases. 
Of those going out to work during the day, 5 inoculated had 
no cases. 
Of those staying at home all day, 16 inoculated had 1 case. 
The fact that the uninoculated persons were equally divided 
between those who stayed at home and those who worked outside, 
and that the two groups returned almost the same percentage of 
cases, indicates that the source of infection was common to both, 
and must therefore have been in the dwelling-house itself. 
The age-distribution of the 53 inhabitants of the eight infected 
rooms was as follows : — 
TT , A e ( 1 1 not inoculated had 7 cases with 2 deaths. 
UptolOyearsofage | 4inocukted „ 0 „ 0 „ 
From 1 1 to 50 years j 20 not inoculated had 12 cases with 10 deaths, 
of age (17 inoculated 1 „ 0 ,, 
A i nTrn f (1 not inoculated had 0 case with 0 death.. 
Above 50 years of age j Qinoculated _ Q ^ 0 >f 
From the above it will be seen that the fatalities occurred mainly 
among those between the ages of eleven and fifty years, and that,, 
though the children show a number of attacks, yet they had a 
smaller death-rate. 
The sex-distribution given below shows that the men were more 
susceptible than the women, but had greater power of recovery. 
All the women who were attacked died, except the one who 
had been inoculated. 
