TEICHINOSIS. 



69 



The ova soon hatch in the ahmentary canal of the host, and 

 the larvEe derived from them commence to lay eggs about six or 

 seven days after their entry. Often by the second day after 

 ingestion the larvre commence to mature; by the fourth day 

 they become mature. The young worms when they come 

 from the ova are extremely minute cylindrical bodies, only 

 2-3irth of an inch in length. They soon commence to bore their 



Fig. 25, — Trichina spiralis. 



A, Piece of diseased porlv (much cnLarged) : en, cyst ; c.c, capsule : w, encysted worm. 

 B, Larva, c, Male. D, Digestive and sexual organs of (^ (after Colin) : oe, oesophagus ; 

 mi, mid-gut ; r, rectum ; T, testis ; vd, vas deferens ; c, cloaca. 



way through the walls of the intestine and enter the sarcolemma 

 of the muscles, penetrating into the primitive bundles, the sub- 

 stance of which degenerates, whilst a rapid increase of the nuclei 

 may be seen to take place. Sometimes the larvte are carried 

 along in the blood. At first the young lie straight in the muscles, 

 but in about two weeks they form a kind of citron-shaped capsule 

 in which they coil themselves up (fig. 25, a). This capsule is 

 derived from the degenerating connective tissue of the muscle 



