226 



THE SHEPHEBD'S MANUAL. 



species of budding, and thus rapidly increase and spread through 

 the bodies of their bearers. The most common of these hydatids is 

 The Brain Bladder-worm, or Ccenurus cerebraMs. This produces 

 the common disease known as turnside, or giddiness, in which the 

 sheep turns its head to the left or right, and walks round and 

 round in a circle in the direction in which the head is turned, 

 until it falls giddy and exhausted. The presence of this parasite 

 has been discovered in the liver of our gray squirrel, and in rab- 

 bits, as well as in numerous sheep in this country. In the sheep 

 it is generally found hi the brain, although it is not peculiar 

 to that organ. It is only there, however, that it produces the 

 usual disastrous effects upon the sheep. Figure 85 represents the 



Fig. 85. HYDATID IN THE BRAIN. Fig. 86. BRAIN WITH FOUR HYDATIDS 



brain infested with but one hydatid (a) ; in figure 86 it has four of 

 them (a, 5, c } d). In size they are from that of a pea up to that of a 

 hen's egg. The hydatid is a bladder filled with a viscid fluid, and 

 covered on its outside surface with marks or oval slits. These 

 slits are the spots to which flask-shaped appendages are affixed 

 within, and are the openings which lead to the interior of these 

 appendages. On examination with a common pocket lens, a por- 

 tion of the bladder appears as in figure 87. The appendages are 

 the necks and heads of the immature tape-worms, each head hav 

 ing four suckers and a series of hooks which are characteristic of 

 the mature creatures, and by which they afterwards attach them- 



