500 



STATE BOARD OF AGEICULTUEE. 



The yonug trichina are like the mature ones, except that the sex organs are 

 but feebly developed. These are found all through the muscles, and can be 

 discerned only by the aid of the microscope. Even the muscle gives no indica- 

 tion to the unaided vision of the presence of this terrible 

 visitor. The young, as seen in the muscle, are generally 

 coiled (Fig. 5), in fact after they reach the ultimate fibers, 

 which they cause to disintegrate, they always coil up, and 

 at last become | of an inch long. Owing to their motion 

 ri<^- 5. and eating an irritation is created, which causes them to 



become encysted or surrounded by 

 a little sack called a cyst or cap- 

 sule. (Fig. 6.) In time there is 

 a deposit of lime in the cyst, when 

 it appears to the eye as a minute 

 speck. 



Now let us trace the life history 

 of these minute, yet terrible de- fig. a 



stroyers. We suppose that man, or a proper animal, as the hog or rat, eats 

 some meat with the young trichina, with or without cysts (Figs. 5 and G) in it. 

 The cysts are soon digested by the gastric juice of the stomach, the same that 

 digests the muscle containing them, when the liberated worms commence a 

 rapid development. In five days they are fully developed, when the females 

 (Fig. 4) become fertilized, and in seven days begin to produce the young, which 

 they may continue to do for six or eight weeks. These minute young at once 

 pierce the intestinal walls, when they are probably carried by the blood to all 

 parts of the body. In fact so rapid is their distribution that no other explana- 

 tion will account for it. In about two weeks the muscular or young trichina 

 attains its maximum size, about l-30th of an inch in length. In four or five 

 weeks the cysts are fully formed, and in about a year the cysts become calcified 

 or receive their deposit of carbonate of lime. Thus these may remain for years, 

 and even decades without becoming extinct, remaining, even though the muscle 

 be salted and smoked, in a dormant state, only awaiting the proper conditions 

 that they may awake from this stupor and again bring ruthless disease and terri- 

 ble death. 



History of the Porh Worm. 



Prior to 1835 this parasite was only known as a calcified cyst, its life history 

 as just given awaiting the more perfect develoimient and use of that most mar- 

 velous of modern instruments, the microscope, for its solution. The finding of 

 these sluggish worms, so snugly domiciled in their capsules, without sex organs, 

 was eagerly appropriated by the advocates of spontaneous generation, as an 

 unanswerable argument in favor of their theory. But with more knowledge, 

 this, like all the other props to the doctrine of spontaneity of life, have toppled 

 and sunk to nothingness. 



From 1835 to 1860 the trichina was studied simply as a matter of scientific 

 interest. To be sure there was a fascination in developing those wondrous life 

 changes, which is ever the rich possession of the naturalist, but the subject 

 lacked tliat pathos which invested it so soon as it was known that in these 

 minute animals existed the germs of a terrible mortality, which might fill our 

 homes with gloom and mourning. Paget discovered the encysted worm, Owen 

 in 1835 described it, giving it the name TricMna spiralis. In 1847 our own 

 Leidy found that the same animal was to be found in the muscles of swine. 



