INTESTINAL HELMINTHIASIS. 



263 



animals try to allay by rubbing the anus, the tail, and the peri- 

 neum against hard objects, or by dragging themselves on their 

 seat ; but these symptoms exist also in other diseases. The abnor- 

 mal dilatation of the pupil, considered by some authors as a 

 pathognomonic symptom of helminthiasis, has no symptomatic 

 value. ^ 



Zurn suspects the presence of intestinal worms in chickens when 

 they show a great avidity for water. 



Concerning the differential diagnosis of the various taenias which 

 may be located in an animal, and also their zoological determina- 

 tion, we have to refer the reader to the treatises on parasites. We 

 here restrict ourselves to giving the principal macroscopic characters 

 ot the most common taenias known in the dog. 



1. Tœnia cucumerina. Often in ball shape, in rings having the 

 form of a gourd — that is to say, a long ellipse — and possessing a 

 genital opening upon each side of the free edge; maximum width, 

 0.002 millimetre; length, from 0.05 millimetre to 0.10 millimetre 

 (rarely 0.20 millimetre); quite thick; the eggs of a reddish shade, 

 in heaps or in cocoon. 



2. Tœnia serrata. Quadrangular rings, joined by rough edges 

 (saw edges), and provided with a genital opening, alternately on 

 the right and the left upon the free edge ; the rings are very long 

 (up to 0.013 millimetre) and wide (about 0.005 millimetre); total 

 length, 0.50 to 1 metre. 



3. Tœnia marginata. Quadrangular rings with regular joints, 

 often wider than long, with undulated edges, and with alternating 

 lateral genital opening. Total length, 2 to 5 metres. This is the 

 widest and the longest taenia of the dog. 



4. Tœnia Cœnurus. White quadrangular rings ; the latter are 

 oblong, and very long relatively to their width. Total length, 0.50 

 to 1 metre. 



5. Tœnia Echinococcus, Formed by three or four rings, and 0.004 

 to 0.006 millimetre long ; the last segment contains the eggs. The 

 rings are white, elliptical, and may be confounded with the intes- 

 tinal villosities. 



Treatment. The tseniafuge remedies are very numerous. In 

 order to act properly they must be given in relatively large doses; 

 in addition, their administration must be completed by the admin- 



1 This dilatation of the pupil is significant in some cases. — l. t. 



