242 



INTESTINAL PARASITES. 



FIG. 90. 



Nerv. 



CEs. 



The larvae of this worm, ingested in infected pork which has 

 been insufficiently cooked, are freed from their capsular encyst- 

 inent in the stomach, and then proceed to the intestine, where 

 they mature in about a week. If not passed out in the faeces, 

 the female worm, which is about 3 or 4 m.m. in length (about 

 three times the length of the male), will burrow into the lympli- 

 spaces, where she deposits her embryos 

 in enormous numbers. These are carried 

 in the blood-stream, and ultimately find 

 lodgment in the voluntary muscles, 

 where they become encapsulated. They 

 are coiled up, either singly or in 

 small groups, in the capsules, which are 

 oval in shape. These latter sometimes 

 become calcified, but in spite of this the 

 larvae may live for a long time. The 

 larvae measure from J to 1 m.m. in length. 

 The parasite may be discovered in the 

 stools early in the disease. In infected 

 meat the larvae are seen as. white specks, 

 which by means of a microscope can be 

 readily examined. Sections may be made, 

 or a small piece of the "specked" meat 

 crushed between a slide and cover-glass. 

 The coil-shaped organism is typical. 

 Staining is unnecessary. 



HOOKWORM (Figs. 90-95). 



By far the most important intestinal 

 parasite to us in this country is the 

 Necator americanus, a member of the 

 strongyloides group, sometimes improp- 



, o %, , , . , r 7 , , -i i 



erly called the Ankylostoma duodenale. 



rj^ ig & ^^ rQund ^^ ^^ 



bling in macroscopic appearance a 

 The female adult measures from 10-12 



Gen. 



faeces -. Nerv., Nervous sys- 



tem; (Es., oesophagus ; int.. 



intestines; gen., genital pri- 



medium; em., anus. > 228. 



small coarse thread. 



m.m. in length; the male, from 810 m.m. The cephalic end 



