NATURE STUDIES. 



lawful habitat. Each attaches itself to tlie lining- 

 membrane of the human intestines, and each by a 

 process of budding produces joint after joint, until 

 man is presented with his matured " guest.-" 



If we tabulate matters thus, the history of the tape- 

 worm will become clear : 



1st Epoch. 



f Stage 1. The egg derived from parent ~] 



tapeworm of man. 

 2. SAvallowed by the pig ; de- 

 veloping. 



2nd Epoch. <( 



3. The "Besting Larva," or 



cystic worm, in the pig's 

 muscles, and forming 

 " measly " pork. 



4. Swallowed by man. 



5. Development of the head and 



neck, and attachment to 

 man's intestine. 



6. The production by budding 



of the adult worm. 



Passed in 



the 

 pig as host. 



Passed in 



man as 



the host. 



As a last piece of parasite biography, we may glance 

 at the history of a form which no\v and then attracts 

 the notice of even Imperial Parliament itself. This 

 form is the famous Trichina, which acquires an un- 

 enviable notoriety, in that it may, unlike the tape- 

 worm race, cause the death of its "host/' Each 

 trichina is a minute worm, coiled, in its immature 

 condition, within a little sack or bag, which in numbers 

 may be found again in the muscles of the pig. Where 

 the pig gets its trichinae from is hardly certain, but 

 rats are believed to be the sources of supply for the 

 pig race. In the muscles of the pig each trichina is, as 



