72 BOARD OF AGRICULTURE. 



the human intestine, or there may be several together, the 

 number depending only upon the number of living young- 

 swallowed. 



It is, therefore, obvious that this tape-worm can be acquired 

 only by eating raw or under-done pork. In this country the 

 principal kinds of food serving as sources of this tape-worm 

 are raw smoked ham and raw sausages, but soldiers and others 

 are often obliged to eat their pork-rations uncooked, and thus 

 obtain the parasites. Our recent war was the means of greatly 

 increasing the numbers of this and other parasites, both in- 

 ternal and external. 



Persons harboring the mature tape-worms become in their 

 turn the means of diffusing the race. Each mature joint cast 

 off contains several thousands of eggs, each of which encloses 

 an embryo, nearly ready to hatch, and as these joints are con- 

 tinually being discharged during the whole life of the worm, 

 which may be ten or twelve years, it is evident that one per- 

 son may thus be the means of diffusing many millions of eggs, 

 most of which will no doubt perish, but the chances are good 

 that some of them will find their way into the stomachs of 

 hogs, either with their food or in water. 



The free joints or proglottides have an independent life for 

 a few days and are capable of moving and crawling about to 

 a considerable extent. In a short time, however, the myriads 

 of embryos in the interior so increase in size that the walls of 

 the proglottis burst open and thus liberate the eggs. The 

 eggs are globular and very small, their average diameter 

 being about ^4 of an inch ; the shell is comparatively 

 thick, being s^W of an inch. They are so small that they 

 may be blown about by the winds, carried on the feet of in- 

 sects, or may be suspended in unfiltered waters. They may, 

 therefore, also readily adhere to lettuce, celery, and other 

 garden plants, or to fallen fruit, especially when night-soil is 

 used as manure, and unless such food be carefully and 

 thoroughly washed, there is always more or less danger of 

 eating the eggs of this and other parasites. When these eggs 

 are swallowed, either by hogs or human beings, they hatch as 

 soon as acted upon by the gastric juice, and disclose their con- 



