larly since the windows are not usually of the best construction.
But the German, with his nearly air-tight double windows and his even
more nearly sealed tile stove, spends the winter in an atmosphere
suggestive of the descriptions that arctic travellers give us of the
air in the hut of an Eskimo. It is clear, then, that the models in the
Museum of Hygiene have thus far failed of the proselyting purpose
for which they were presumably intended. How it has chanced that the
inhabitants of the country maintain so high an average of robust health
after this open defiance is a subject which the physiological department
of the Institute of Hygiene might well investigate.

Even though the implied precepts of the Museum of Hygiene are so largely
disregarded, however, it must be admitted that the existence of the
museum is a hopeful sign. It is a valuable educational institution,
and if its salutary lessons are but slowly accepted by the people, they
cannot be altogether without effect. At least the museum proves that
there are leaders in science here who have got beyond the range of
eighteenth-century thought in matters of practical living, and the
sign is hopeful for the future, though its promise will perhaps not be
fulfilled in our generation.

VII. SOME UNSOLVED SCIENTIFIC PROBLEMS

IN recent chapters we have witnessed a marvellous development in many
branches of pure science. In viewing so wonderfully diversified a field,
it has of course been impossible to dwell upon details, or even to
glance at every minor discovery. At best one could but summarize the
broad sweep of progress somewhat as a battle might be described by a
distant eye-witness, telling of the general direction of action, of
the movements of large masses, the names of leaders of brigades and
divisions, but necessarily ignoring the lesser fluctuations of advance
or recession and the individual gallantry of the rank and file. In
particular, interest has centred upon the storming of the various
special strongholds of ignorant or prejudiced opposition, which at last
have been triumphantly occupied by the band of progress. In each case
where such a stronghold has fallen, the victory has been achieved solely
through the destructive agency of newly discovered or newly marshalled
facts--the only weapons which the warrior of science seeks or cares for.
Facts must be marshalled, of course, about the guidon of a hypothesis,
but that guidon can lead on to vict