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112
such breakdowns numbered 2, or 0.6 per cent. of the
cases notified. It may be noted here that the
secondary case in group 33 occurred in the same
house but in another family and tenement.
So far it appears that in 3.0 per cent. of the
disinfections after scarlet fever, and in 0.7 per cent.
of those after diphtheria, the process of disinfection
may have been inefficient. In a communication to
the British Medical Association, read at the Annual
Congress of 1896, Dr. Kenwood reported that he had
collected statistics from 6 sanitary areas in and around
London with reference to 1,330 disinfections of
premises after scarlet fever and diphtheria. Taking
the view that all cases occurring within fourteen days
after such fumigation—a view which he stigmatises
as "extreme and unjustifiable"—he found that there
had been 55 cases so attributable to defective disinfection,
equal to 4.1 per cent. of the total disinfections
performed. The 55 cases included cases of both
scarlet fever and diphtheria. For the purpose of
making some comparison with Dr. Kenwood's result,
the number of times secondary cases occurred within
fourteen days of disinfection have been determined.
During the year 686 disinfections were carried out,
and after 58 operations, secondary cases were reported
within fourteen days—giving a percentage of
"breakdowns" on Dr. Kenwood's supposition of 8.4.
For reasons already set out, no value is attached to
this mode of examining the question.