MORBID ANATOMY 



357 



~d - - - ^ 



Fig. 69. Cross seclton oj intestine con- 

 taining nodnles. b. mucous membrane, c. 

 submucosa, d. muscular layers, e. e. section 

 through cheesy nodules. ( Curtice. ) 



■histor^^ Yearlings may show considerable infection, but it 

 is usuall}- in older 

 sheep that the most 

 abundant infection oc- 

 curs. The disease is 

 a seasonal one, in that 

 it can be found in best 

 development in the 

 winter. The lambs 

 begin to be infected 

 in the summer and fall and from that time the tumors formed 

 increase in size until early in the spring of the next year, when 

 they gradually grow smaller but probably do not entirely dis- 

 appear. 



A study of the fresh tumors by compressing the smaller 

 ones between two glasses and by dissecting larger .specimens 

 gives the following results. The small tumors, which are 

 scarcely the size of a pinhead, are found in the submucous 

 tissue. They appear like a .sac filled 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 in- 

 closed. By careful dissection the cyst may be separated and 

 finally the worm itself may be removed. In an older cyst there 

 is a greenish, cheesy-like substance present. 



When the little nodules 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 fresh tumors the worm is 

 found in the ma.ss 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, yellowi.sh-green at the 

 other. It is in this end that the worm is found. If some of 

 the harder nodules are examined, it may be found that there 

 is no greenish material in them and no worms. These hard 



