clean, but in dry weather, unless the road watering be unstinted,
more harm than good will accrue from scavenging, as the dust finds
its way into the dwellings. The sweeping should take place while
the surface is moist.
A more potent factor, probably, is the state of the yards at the
rear of the dwellings. Though there is no excuse for the accumulation
of refuse around houses, it is surprising how often this nuisance
occurs. The air space around the smaller houses is sufficiently
limited, but the Inspectors constantly have to draw attention to all
kinds of deposits which are allowed to accumulate.
It must be admitted, though, that the fault does not always lay
with the householder. The backyards of some of the older premises
are insufficiently and improperly paved, and however careful one
may be, it is almost impossible to prevent the impregnation of the soil
with organic matter unless a portion of the backyard be imperviously
paved. The work of enforcing the bye-laws as to paving of backyards
and open spaces is gradually and continuously carried out.
and it is hoped that very soon every house will conform with the
These considerations do not fully explain the coincidence between
earth temperature and the incidence of Diarrhœa. High earth
temperature means a previous high air temperature, and high air temperature
means an enhanced rate of multiplication of the microbes
present in milk, together with the formation of dust, which may play
a considerable part in the contamination and infection of the food.
But a high air temperature commenced towards the latter part of
June, 1906, and continued in an intense form throughout July, but
the deaths from Diarrhœa did not start until August. During July
there was no death from Diarrhœal diseases.
Dr. Nash has pointed out that the diarrhoea curve closely follows
the life-history of the common house-fly, and he suggests that they
art largely responsible for the infection of food, which is the ultimate
cause ot the disease. He suggests that if, instead of Ballard's microorganism.
we merely say an organism whose manifestations are dependent
upon conditions of season, we shall be nearer the truth; and
he suggests that this organism is the common house-fly. which, beginning
to make its appearance in June, becomes a veritable pest
during July and the early part of August; after that its existence tends