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be seen from diagram XXVII. most of these were successful in catching secondary cases; but the
experience demonstrates that the more successful one is in closing the more closure must be applied,
for two classes were closed no less than three times each durirg six months, and another twice in three
months.
Deansfielcl Road School.—This is a temporary school, consisting of three classes; a case of
measles appeared in Class C on January 18th ; this class was closed from January 26th to February
4th. The first crop, however, came down equally in Classes A and B, and practically exhausted all
the material. The second crop was almost negligible. Only three cases in the whole school who
were reported not to have previously had measles escaped ! Although the whole school was closed
upon the earliest opportunity the closure did not the least good; here again is demonstrated the
effect of unhygienic school conditions on the spread of disease, practically every child taking
measles at the very first opportunity (diagram XXVIII).
The reliability of the histories of measles obtained on admission of children to school is a most
important consideration. It has previously been pointed out (in the First Annual Report, 1903)
that the similarity in the curves of the various schools, and the regular increase of the proportion
of the children who have had measles as we pass from the age of 3 to that of 8 is strong presumptive
evidence of the very considerable reliability of the histories. We may now apply a test from the
facts gained by experience; this test depends, however, upon the amount of protection given by a
previous attack of measles. Most observers agree that one attack protects the individual to a very
considerable degree, probably in by far the greater majority of children the protection is absolute;
but it is doubtful if a single observer would say this is invariably the case, and most medical men
will assert they have seen second attacks. Let us assume, however, the position that the
protection given by a first attack is absolute, and any second attack reported proves that the history
of the first attack was an error. The distribution of the cases occurring during the past year
amongst those reported to have had measles and those reported not to have had measles is given in
the following table :—