1893.] 



MICROSCOPICAL JOURNAL. 



155 



parasite, tlic- male, in its fiilK dtvelopcil aiul sexually iiiatiiie con- 

 dition, measuring; about i-iSth of an inch, while the perfectly 

 developeil females, which are ten times as numerous as the oppo- 

 site sex, are over double that lenj^th. Their bodies are rouiul and 

 taper slightly from the midille toward each end. The head is 

 narrow, finely pointed, unarmed, and with a central minute oral 

 aperture. The mode of reproduction is viviparous. As usually 

 found it is encased in its protectinj^; capsule, which is about 1-140 

 by i-i20th of an inch in diameter. These cysts or capsules are 

 sometimes visible to the naked eye, as represented in I'ig. 2, 

 measuriiiiij i-iooth inch in width bv i-6oth inch in length, while 

 the worm itself, stretched out, is abo t i-28th of an inch long by 

 i-5CK)th ot an inch wide at the middle of body. 



The human eye is capable of separating lines i-200thof an inch 

 apart without the aid of a lens, so \ou may know that by trans- 

 mitted light, and in thin sections of meat, these capsules may be 

 readily observed. They appear like small round dots, granules, 

 vesicuUe. or streaks, grayish white, and quite distinct from the 

 red, transparent muscle. When numerous, they sometimes im- 

 part a specked appearance to the meat. Thcv can be readilv 

 seen by the aid of the 

 microscope under an 

 amplification of 75 

 diameters, and are 

 well illustrated (en- 

 capsulated) in Fig. 2. 

 which is an isolated 

 specimen chosen to 

 show the character- 

 istic appearance of tlic 

 closed capsule. This 

 is the form in whicli 

 they usually exist in 

 infected meat and are 

 taken into the human 

 stomach. When meat 

 containing such en- 

 cysted trichina? is eat- 

 en, the action of the , , ,. . . 



,. ^. n • 1 1 • Fig. 2. — Human flesh magnified 75 diameters showing 



digestive tlUldS, bemg Trichinae in capsule. 



acid, dissolves or soft- 

 ens the capsules, which is of a calcareous or lime consist- 

 ence, and the animal heat of the body animates the parasite to 

 renewed exertion, so that it bursts the capsule (Fig. 3) and escapes 

 into the intestinal canal, where it enters upon an active career, 

 increasing in size and sexual activity. 



About the second day after their introduction, the intestinal 

 trichinai attain their maturity, lose their spiral shape, and become 

 stretched, while they grow rapidly in sexual activity. Most 



