THE ANATOMY OF THE HORSE 75 



blood, from which the milk is secreted. On the under side of 

 each gland is found the teat, or that part taken hold of by 

 the young when sucking. The end of the teat is pierced by 

 several small holes, through which the milk passes. 



III. — THE FOETUS, OR YOUNG ANIMAL BEFORE BIRTH. 



We must here first speak of the ovum, or egg, 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, or egg, passes down the tubes before 

 mentioned into the womb, 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 fcetus, or foal. The foetus may be for conveni- 

 ence divided into three parts, viz : the foetus proper, the navel 

 string, and the cleanings, or placenta. The cleanings, or 

 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 

 cleaning or 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 cleaning 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 speaking 

 of the lungs. The fcetus, 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. Be- 

 tween the thirty-fifth and the fortieth week the foal begins 

 to show signs of life, and is completely covered with hair. 

 \fter this time it grows very rapidly and may be 



