170 



with fluid and having a little globe floating within. By using a higher 

 magnifying power the little globe is seen to be a cyst with a worm 

 inclosed (see Plate XXV, Pig. 6), By careful dissection the cyst may be 

 separated (Fig. 5), and finally the worm itself may be separated (Fig. 3). 

 At this stage the worm shows little differentiation of parts. In exam- 

 ining another and older cyst (Plate XXV, Fig. 7) the same appearance 

 may be observed. There is also a little greenish, cheesy substance 

 present. A third stage (Plate XXVI, Fig 3) shows the latter still fur- 

 ther increased, and in the figure referred to the arrow shows that the 

 encysted worm has been pressed out of this mass, leaving a cavity be- 

 hind. 



When the little tumors become larger than a pinhead and entirely 

 filled with the cheesy matter their structure does not materially change, 

 but is more difficult to make out. It is at this stage that the worm 

 escapes from the cyst and begins to wander within the capsule which 

 its presence in the tissue has caused. On dissecting the large Iresh 

 tumors the worm is found in the mass of cheesy material, which is now 

 quite abundant, filling the cavity and producing tumors as large as 

 the end of one's finger. This cheesy material is usually hard, dry, and 

 brown at one end, and soft, yellowish-green at the other. It is in this 

 end that the worm is to be found. If some of the harder tumors are 

 examined, it may be found that there is no greenish material in them and 

 no worms. These hard tumors may be of all sizes and are found at all 

 times. From these the worm has either escaped or in the case of the 

 smaller tumors the worms have died. The form of these tumors is 

 usually spherical, but the cheesy material may appear as a long mass, 

 or it may apparently fill what seems to have been a worm track. The 

 last appearance occurs most often in the small intestines. From the 

 nnicous side these tumors present little if any color. The older ones 

 may present a greenish-yellow appearance, especially if the mucous 

 membrane over them be thin. In well-advanced cases, when the tumors 

 are numerous and large, manj' are found in which the mucous membrane 

 over them is ruptured and the cheesy mass protrudes into the intestinal 

 cavity. In these no worms have been found, and hence the conclusion 

 has been reached that the worms have escaped. 



In lambs the little dots indicating the presence of the young tumors 

 are very scattering (see Plate XXVI, Fig. 1), but in older sheep tijoy 

 may be very numerous (see Plate XXVIl, Fig. 1). Between the stage 

 in which a few are scattered here and there over the caecum and that 

 in which the caecum has become a stiff tube with walls from one-fourth 

 to one-half inch in thickness (so thick and close have the tumors be- 

 come) there are all varieties. The tumors may extend from the caecum 

 to the anus. They may also be abundant along the small intestine. 

 The cheesy material which the worms produce has been found in the 

 lymphatics, on the omentum, and in the liver, but in these places it 

 Bever seems to be sufficiently abundant to show that the parasite lived 

 long. 



