258 



How THE FARM PAYS. 



being from their natural weakness unable to strive successfully against 

 the exhaustive effects of these parasites, which live upon the vital 

 fluids of the animals, besides producing intolerable and fatal irritation 

 in the organs in which they find their abode. The most important of 

 these injurious parasites are tape worms, and these are more especially 

 worthy of notice because they not unfrequently find a lodgment in 

 the human body and produce distressing inconvenience and disease. 

 Sheep suffer most from these parasites, one of which finds its resting 

 place in the brain, and produces the very common disease known as 

 " gid " or " turnside," so called because the animal appears giddy, or 

 turns around continually towards one side in a circle, until it drops 

 and dies in convulsions. This pest is known as the Brain Bladder 



SHEEP BRAIN BLADDER WORM. 



THE WORM ENLARGED, AND 

 THE SACS OF NATURAL SIZE. 



Worm, from its appearance as watery bladders in the brain of the 

 sheep. The worm gains its entrance into the sheep's brain in the 

 following curious manner. The mature worm inhabits the intestines 

 of the dog, and its eggs are discharged in the dung which is dropped 

 in the fields near fences, stones or trees or on tufts of grass, as is the 

 habit of the dog. The sheep loves to nibble such tufts of grass, and 

 in swallowing the herbage also swallows with it the eggs. These are 

 very small, and when in the stomach are absorbed into the lacteal 

 vessels and carried into the veins, and those which reach the brain 

 remain there, forming around themselves thin envelopes like bladders, 

 which become filled with watery fluid absorbed from the blood. In 

 the engraving is shown the brain of a sheep having one of these 

 bladders in it. The bladder contains a great many small sacs, one of 

 which is also shown separately, each containing an embryo tape worm. 

 When these bladders are numerous in the brain, they produce such 

 disturbance of that organ as to cause the peculiar effects above described 

 and the slow death of the animal. The disease is most prevalent in 

 the winter, and the past season (1884) has been especially disastrous 



