TMNIA. 



79 



Fig. 27. 



instances the spinal cord. It is seen in all ruminants, especially 

 sheep. 



Tseriia Bchinococous. (Fig. 27.) This is the smallest taenia 

 of the dog. Its greatest length is 4.4 mm., and it has three and 

 in rare instances four segments. The last segment is the largest 

 and the only one to possess sexual organs. The uterus is large 

 and irregular, without any central body, and a 

 sexual orifice which is located at the border. 

 The head is round and has four sucking disks 

 and twenty-eight to forty-six small, imperfectly 

 developed hooks, arranged in two rows. The 

 eggs are round and slightly elongated, the shell 

 being formed in several layers. The bladder- 

 worm is the echinococcus polymorphus; the 

 bladder is filled with a non- albuminous fluid, 

 and generally has daughter-cysts on the sides. 

 These cysts may assume enormous proportions, 

 ranging in size from a pea to a man' s head or 

 even larger. It is found in the pig, cattle, and 

 sheep, and very rarely in the horse, but quite 

 frequently in man, especially in Iceland and 

 Australia. It is generally found in or attached 

 to the liver or peritoneum, but it has also been 

 found in the lungs, kidneys, spleen, muscular 

 system, pleura, bones, and the brain. 



Cli^tical Symptoms. "When tapeworms are present they gen- 

 erally cause more or less disturbance in the host. Often they pro- 

 duce the same symptoms as ascarides, but, as a rule, they cause 

 much more trouble than the round worms. Schieferdecker found 

 that in the duodenum, where the taeniae cucumerina are gener- 

 ally found, the mucous membrane had numerous small tunnels, 

 through which the taeniae passed in and out, and a peculiar 

 hypertrophy of the papilla. In some cases they were four or five 

 times their own length. In other cases Lieberkiihn's glands were 

 sunken and collapsed and in several cases had completely disap- 

 peared. The taeniae echinococcus, when they are present in large 

 numbers, cause great irritation of the intestines, with hemorrhagic 

 infarction of the tissues. In irritable animals they cause epileptic 

 spasms or even symptoms of rabies, such as change of voice, paral- 



Tsenia echinococcus : 

 a, tapeworm, enlarged 

 twelve times ; 6, cyst 

 containing head ; c, 

 Immature head. 



