SUMMER CARE AND MANAGEMENT. 133 



years and his • farm perhaps so infected with 

 germs of parasites that there is no longer any 

 profit in keeping sheep there. 



Most of the trouble comes from the internal 

 parasites, and while there is a long list of 

 them that afflict sheep nearly all the trouble 

 in our country comes from two or three spe- 

 cies. By far the most prevalent and trouble- 

 some is the twisted stomach worm (strongylus 

 contortus). This inhabits the fourth stomach 

 of the ewe and she carries it through the winter 

 even though she may seem to be in good 

 health. In spring and during summer tlie 

 worms become filled with eggs, "ripen" and 

 pass away. Just how the young germs then 

 re-enter the sheep or find a home in the more 

 tender stomachs of the young lambs no one 

 knows. Tliey probably hatch in shallow pools 

 of stagnant water (infections in Texas and 

 New Mexico are thought to be by this means) 

 or they attach themselves to the moist grass 

 close to the ground and are taken in from 

 that position. It is noticed that old and rich 

 sheep pastures covered with short, sweet grass 

 are frequently the most fatal to young lambs 

 even wheai there is no stagnant water with 

 them. 



It is not too much to say that the stomach 

 worm has done m.ore to discourage sheep hus- 

 bandry in the corn-belt of America than all 

 other causes put together and many a man 

 has gone out of business from the depreda- 

 tions of this tiny enemy who did ngt even 

 know that such a pest existed. 



