110 



BOARD OF AGRICULTURE. 



diameter of one-eighth to one-fifth of an inch. The females 

 may become six inches, or even a foot in length, and some- 

 times one-quarter of an inch in diameter, though generally 



Figure 74. 



smaller. The female is very prolific, producing an immense 

 number of somewhat oblong-oval eggs. 



The history of its development and transformations has 

 not yet been made out. There can be little or no doubt, 

 hovs^ever, that the young worms are parasitic in some other 

 animals, — most likely in insects, worms, or snails, — and that 

 the hogs get them by devouring the embryos included in 

 some such small animals. 



Effects and Symptoms. 



This is the commonest and most injurious intestinal worm 

 found in swine. These parasites live in the small intestine, 

 and more rarely in the large intestine. They usually adhere 

 to the lining, or mucus membrane, by means Fiom-e 75. 



of the hooks on the proboscis, which is thrust 

 into the substance of the membrane. Not 

 unfrequently they perforate the walls of the 

 intestine and stray into other parts of the 

 viscera, producing serious disease. Some- 

 times the intestine of a hog is found per- 

 forated by so many of these holes that it can- 

 not be used in the manufacture of sausages ! 



In severe cases, hogs afflicted with this parasite are weak 

 in the loins, and have the membranes in the corners of the 

 eyes swollen, watery, and lighter colored than usual. The 

 excrement is hardened and highly colored, and the animal 

 often keeps up a continual squealing and grunting, especially 

 in the morning. Such hogs are generally cross and morose, 



Figure 74. — Echinorhynchus gigas, natural size. From Cuvier. 

 Figure 75. — Head of £. ^rigfas, enlarged showing the reticulated vessels in the 

 skin. From Cuvi.er. 



