540 THE TRICHINA. 



curious characteristics. It is very large, in comparison with the body, and has four deep clefts 

 set opposite to each other. Some of the species have only two of these clefts, which, in the 

 Greek language, are called "bothria," but in all the genus either two or four of these clefts 

 are to be found. The generic title literally signifies "furrow-headed." 



One species of this genus (BothriocepTialus latus) is the well-known BROAD TAPE-WORM, 

 which is so injurious to man whenever it takes up its abode within a human being. This 

 creature will sometimes attain a length of twenty feet ; and it may always be recognized by 

 the peculiarly deep and opposite furrows on the head. Like all its kind, this Tape-worm 

 increases with great rapidity, multiplying its joints by division, and in that manner extending 

 itself to the great length which has already been mentioned. 



The whole history of these strange creatures is very obscure, on account of the impossi- 

 bility of watching them in the spots wherein they take their residence. They are all, as is 

 generally the case with beings low in the scale of nature, exceedingly tenacious of life, and 

 will survive treatment which would kill many beings apparently stronger and more capable of 

 resistance than themselves. For example, several species of Entozoa have been found in a 

 living state within meat after it has been cooked, especially in those spots where the heat had 

 not penetrated sufficiently to destroy the natural ruddiness of its color. It is known that 

 "measly" pork derives its peculiar aspect from the presence of Entozoa, and that many of 

 these Entozoa, or, at all events, their eggs, are swallowed by human beings, within whom they 

 make their homes, and whom they condemn to infinite worry, pain, and weakness. 



Even immersion in alcohol does not seem to inflict any serious damage upon these creatures. 

 Rudolphi found a specimen of an Ascaris quite lively in the throat of a cormorant that had 

 been steeped in spirits of wine for nearly a fortnight. Even the severe process of being 

 thoroughly dried appears to be quite as ineffectual to destroy these being*. A number of 

 Ascarides that had been removed from a fish, and suffered to become quite dry, and were 

 apparently nothing more than flat slips of membrane adhering to a board, began to revive as 

 soon as they were wetted, and actually moved the moistened part of their bodies, while the 

 remainder was still dry and adhering to the board. 



THE TRICHINA is a parasitic nematoid worm, which infects the muscular tissue of the pig, 

 the rat, and some other animals, and is liable to occur in man. It is usually a quiescent 

 incysted parasite, occupying in great numbers, often, the voluntary muscles. The process of 

 development of Trichinae in the intestine, and the dispersal of their young throughout the 

 system, produces in men and animals a severe and often fatal illness, known as trichinosis 

 severe intestinal irritation, with fever, are common symptoms. No remedy is found effectual 

 in staying the ravages of this dreadful parasite, other than extreme cleanliness and caution. 



The use of food imperfectly cooked is the great source of trouble. The fat of pork is not 

 injurious, as the Trichinae never infect that portion. The muscular parts, as in sausages, 

 fresh pork, ham, and the lean parts of bacon, are liable to produce the disease. The parasite 

 is so small that the butcher often cannot tell whether any given piece of pork is affected or 

 not. Neither pickling nor smoking, as ordinarily practised, will destroy the life of the pest. 

 The only protection is by very thorough cooking. The Trichinae are killed by a temperature 

 of 160 Far. Meat that is subjected a short time to this temperature is harmless. All parts 

 of the piece of meat should be carefully heated at that point, as a ham may be at 160 on the 

 surface, while inside the temperature may be much lower. The only safe rule is to boil until 

 the meat is of a uniform color throughout. 



