The pregnant sow usually carries her pigs about sixteen weeks. The variations are neither great nor numerous, when they do occur it is usually with sows with their first litters or aged sows which sometimes farrow ere the full time has expired, or with robust sows in good condition which occasionally carry their young beyond the one hundred and twelve days which may be taken as the average period. We assume that each owner of a breeding sow keeps a record of the date of service of the sow in order that the necessary preparation of the sty, etc., can be made in readiness for the arrival of the expected litter. Even when this wise precaution is neglected nature gives a sufficient warning to the observant owner. Apart from the increasing size of the body, the udder gradually becomes more prominent, and each pap becomes more defined, the vulva becomes enlarged and the muscles on either side of the tail fall away and lose their tenseness, whilst in the vast majority of cases milk appears in the udder some twelve hours before the arrival of the pigs. The teats shine and become more prominent, the presence of milk is easily ascertained by gently pressing the teat between the finger and thumb. Another certain indication of the early arrival of a family is the act of the sow carrying straw about in her mouth wherewith to make her farrowing bed. One of the chief causes of trouble with the farrowing sow arises from the sow not having been allowed to take sufficient exercise. Of course, the best of all systems is to allow the sow its complete freedom at all seasons of the year save when she is within about a fortnight of her time, and when she is rearing a litter of pigs. Even if there be no grass field or paddock in which she is able to pick up a good portion of her living, or a roadside where she can get a few blades of grass, an open yard is infinitely better than the confinement of a sty, as apart from the reduction in the cost of keep, the sow will produce stronger pigs, and have a decidedly easier time of farrowing. In the case of a sow showing a disinclination to take a sufficiency of exercise either owing to laziness, to high condition, or heaviness of body, it is advisable to exercise her by walking her about quietly for a short time each morning and evening before and after the heat of the day has become excessive, or has passed off.