210 



LO WKR INVER TEBRA TES. 



Flo. 19G. — Trifhi 

 spiralis encystoii 



tlie discliarge of the ulcer serves to set free lh(> brood of youtis;, but tlie histoi-y of 

 the s])ecies lias not yet been furtlier elueidateil. 



Tlie Tkiciioteachei.id.k include the most dans^erous by far of human parasites, the 

 one which most often and most I'ajiidly i)roves fatal to the life of its host, the much- 

 feared trichina. The worm occurs in little distiiiet ca|)sules in the muscles of the 

 body of many animals; now wln-u some ot' the infested muscles of one animal 

 is eaten by another, the capsule is dissolved by the action of the digestive juices, and 

 the larval worms arc liljerated in the intestines of their new host, where in the course 

 of a week they become mature and then produce millions of eggs, which soon hatch 

 out minute larva\ The larva? shortly ])enetrate the walls of the intestine and wander 

 about through all parts of the body, injuring and irritating all the 

 tissues they traverse. Finally they settle down in the muscles, 

 ])enetrate the muscular fibres, feed on the substance thereof, and 

 grow in a few weeks to several times their original size. While 

 wandering and growing they jiroduce the most serious consequences 

 in the health of the host, and being often present literally in millions, 

 the accumulated effects of all the slight injuries ])roduced by eacli 

 tiicliiua cause the greatest suffering to their victim, and often lead 

 to his death within a few weeks. Still the host may be restored to 

 good health if he can survive the first few weeks of danger; for 

 after the trichiuie are established in the muscle fibres and have 

 finished their growth, there they remain for yt;ns and years, en- 

 closed in tough capsules, in which they lie coiled in a spiral. In 

 tills stale they jiroduce no serious injury, and, as after the first attacks are over, and 

 the inflammation they cause lias subsided, the muscles and other injured tissues of the 

 host are regenerated, there may be a complete recovery, .-iftei- passing through the first 

 period of danger. 



Pigs, from their omnivorous liabits, are peculiarly exposed to the attacks of tri- 

 china}. In some German towns it was found that one pig in every tliree hundred or 

 even less was infested; now such a pig slaughtered and made into sausages and 

 uncooked ham has often served to feed nearly a whole Gorman village, and thus to 

 cause a veritable epidemic of trichinosis. In 1SS4, shortly after the exclusion of 

 American jiork from Germany, ostensibly because of tlie danger of trichina;, there 

 occurred one of the most frightful eiiideniics just in the manner told above. From 

 one jiig the parasites were conveyed to three hundre(l nnd sixty-one known persons, of 

 whom no less than fifty-seven died within four weeks. This was in the villages around 

 Emersleben, Saxony, having only about sixteen hundred inhabitants. Such outbreaks 

 have been by no means uncommon in Germany, owing to the habit universal there of 

 eating raw or imperfectly cooked meat. To e\ cry ]irudent 

 person it has become an inviolable rule, ne\ er to eat any 

 sausage, pork, or ham, which has not been very thoroughly 

 cooked, so that any encapsuled trichina^ in the meat may 

 have been killed by the heat. 



The trichina; are found in the muscles in immense num- 

 bers, and often closely crowded together, each worm looks 

 like a coiled liair, whence the name Trichina spiralis. 

 The oval capsules are not over a fortieth of an inch in length, while the worm 

 of course is very much smaller, and always coiled. They were first found by Hil- 



Fio. im. — Trichina sjiiralis 



