134 Proceedings of Royal Society of Edinburgh. [sess. 
and lived under similar conditions; thirdly, because the com- 
munities were equally exposed for a period of six weeks to an out- 
break of plague which carried off 6*2 per cent, of the uninoculated 
and, lastly, because the results appear to have been accurately 
verified. From this experiment we learn two lessons. Firstly, we 
learn that the number of plague attacks among the uninoculated 
is much larger than that among the inoculated ; in this particular 
case, as the table given above will show, plague attacks were 
proportionately four times more numerous among the uninoculated 
than among the inoculated. The second lesson we learn is that 
the percentage of deaths among the attacked is very much higher 
among the uninoculated than among the inoculated ; in this 
particular case, as the table again shows, the percentage of deaths 
among the uninoculated was proportionately ten times as great as 
among the inoculated.” The only sentence in the above remarks 
which seems to indicate that the members of the Commission were 
not quite satisfied is that in which they say that the numbers in 
the two groups of * inoculated ’ and ‘ uninoculated ’ were deter- 
mined with “ a considerable degree of accuracy.” This remark 
detracts considerably from the value of the approval thus bestowed,, 
and it will be well to examine whether the errors are likely to be 
serious. 
The two objections put forward are — (a) that the census was- 
made a month before the inoculations were performed, and ( b ) that 
the number of uninoculated “ appears to have been ascertained not 
by a direct enumeration hut by computation.” Now with regard 
to the first objection, it is certain that no one would come to the 
village while plague was raging in it, therefore the population 
would not be increased in the interval. We know that ten persons 
left the village during this time, and it is unlikely that more did 
so, for we used the census papers at the time of inoculation, as a 
means of getting at all the people, and if any had been absent it 
would have become apparent to us as we proceeded from house 
to house. Now beyond these ten who had left and a few men 
absent for the day at market, none remained on the list un- 
accounted for. I consider, therefore, that the census was accurate 
in a high degree and not merely in a considerable degree. But 
even supposing a large number of men had departed from the 
