In formulating rules for the construction and care of stables and the
disposal of manure the following points must be taken into
consideration. In the first place, the ground of soil-floor stables may
offer a suitable place for the development of fly larvæ. The larvæ will
migrate from the manure to the soil and continue their growth in the
moist ground. This takes place to some extent even when the manure is
removed from the stables every day. Even wooden floors are not entirely
satisfactory unless they are perfectly water-tight, since larvæ will
crawl through the cracks and continue their development in the moist
ground below. Water-tight floors of concrete or masonry, therefore, are
desirable. Flies have been found to breed in surprising numbers in small
accumulations of material in the corners of feed troughs and mangers,
and it is important that such places be kept clean.