THE DEVELOPMENT OF THE YOUNG.--We must here first speak of the ovum or germ, which is secreted by the ovary of the mare. Every time she comes in season (which occurs every three weeks during the hot weather) this ovum passes down the tubes before the womb as before mentioned, where it remains a few days and then dies if she is not put to the horse; but if, during the time this ovum is in the womb she is put to the horse and one of the spermatozoa from the semen of the horse comes in contact with it (the ovum) and a union of these takes place, then the rest of the semen dies and passes away, and the neck of the womb contracts gradually until it is perfectly tight. These two little bodies begin to grow when united and form the foetus, or foal. The foetus may be for convenience divided into three parts, viz.: the foetus proper, the navel string, and the placenta. The placenta is the part which is found covering the foal and is attached to the little pea-like elevations on the inside of the womb. This covering is found to be full of small blood vessels which finally unite to form two larger vessels, known as the navel veins. These carry the blood up through the navel opening of the foal and then to its heart. By the action of the heart it is forced all through the body of the foal and returned again to the heart. It is then forced down another artery to the navel opening, along the navel cord, into the placenta again, where it is distributed through the small blood vessels. When the blood comes down this cord from the foal it is in its impure state, and while it is passing through these small vessels in the placenta it comes very close to the small blood vessels in the womb. The blood is cleansed and nourished from the blood of its mother by a process similar to that which was spoken of when describing the lungs. The foetus, or foal, does not grow so fast the first month as it does later on. At the age of seventeen weeks the first hair appears on the lips and the tip of the tail. Between the thirty-fifth and the fortieth week the foal begins to show signs of life, and is completely covered with hair. After this time it grows very rapidly and may be seen moving around by watching the flank closely. The mare carries her foal eleven months, but in some cases an aged mare has been known to carry her foal over twelve months. In rare cases young mares may lack a few days of eleven months. The Average Periods of Gestation of Domestic Animals. Mare 11 months Ass 12 months Cow 9 months Sheep 5 months Goat 5 months Sow 3-1/2 months Bitch 9 weeks Cat 8 weeks