The parasite especially inimical to colts is the =tænia= or =tape-worm=. It is mostly perpetuated by the farmer's prejudice, which procures foals from dams that are done up for work: which starves the mother till her produce runs by her side, and which attempts to rear young stock upon the sour grass of a public common. Both sire and dam should be in perfect health if a valuable colt is desired: neither can be too good. The mare should not, during gestation, be "turned out" to distend the abdomen with watery provender--to have the stomach and intestines filled with bots--to allow filth and excretions to accumulate upon the coat and to check the healthy functions of the skin. Gentle work, only sufficient to earn the stable-keep, will injure no animal. The mare will rather be benefited by _moderate_ exercise, and by also having all the food and attention to which she has become habituated. But to expose a mare during the summer months, and to stint the animal during the winter season, can produce nothing which shall repay the expense of rearing. The little progeny before it sees the light is the inhabitant of an unhealthy home; after birth the mother's secretion is thin, poor, and watery. It neither satisfies the cravings of hunger nor can nourish a body into growth. Ill health in the young encourages parasites. The colt soon becomes the prey of the tænia. [Illustration: IRRITATION CAUSED BY WORMS. THE NOSE RUBBED VIOLENTLY AGAINST A WALL.] The young when afflicted with the above parasite may not die, but they are reserved for a miserable and a useless life. The developments are checked. The foal grows up with a large head, low crest, tumefied abdomen, and long legs. If it be a male it cannot be operated upon before the fourth year; even then it is cast only because there is no hope of further improvement. The appetite during the long time of rearing is more than good; the ribs, nevertheless, are not covered with flesh; the dung is not well comminuted--it is friable and sometimes partially coated with slime; the anus projects--occasionally it is soiled by adherent strips of tenacious mucus, almost like to membrane; the coat is unhealthy; the breath fetid; the animal may rub its nose violently against a wall or remain straining it upward for a considerable time; the eye becomes unnaturally bright; the colt begins to pick and bite its body, often pulling off hair by the mouthful. [Illustration: A COLT PICKING THE HAIR FROM ITS LEG BECAUSE OF WORMS.]