PARASITES AND THEIR DEVELOPMENT. 199 



the result of the preliminary processes of digestion in the 

 stomach is the dissolution of the little cysts, and the con- 

 sequent liberation of the "juvenile" population. In two 

 days thereafter, the precocious "juveniles," influenced by 

 the change of life and situation, have become mature 

 trichinae; and, after the sixth day, enormous numbers of 

 eggs are produced by these matured forms. After this 

 stage has been attained, the parent parasites become of no 

 further account in the history of the host, but the young 

 form the subjects of grave concern. This new generation 

 is found to be a restless and migratory body, and influenced 

 by the habits of their ancestors, the young pass from the 

 digestive organs, through the tissues of the body, to seek a 

 lodgment in the muscles. Now comes the tug of war, for 

 the host at least. With thousands of these microscopic 

 pests boring their way through his tissues, there is no lack 

 of explanation of the excessive muscular pains felt by the 

 trichinaised patient. But relief comes in due course when 

 the restless brood has located itself in the muscles. There 

 each young trichina developes around itself a cyst or capsule, 

 and returns to the primitive form in which we first beheld 

 it. There, also, it will rest permanently, and degenerate 

 into a speck of calcareous matter unless, indeed, an un- 

 looked-for contingency arises. Were cannibalism a fashion- 

 able vice amongst us, the eaters would receive from the 

 muscles of the eaten the young population of trichinae, just 

 as the original subject received the juvenile brood from the 

 pig. Within the cannibal organisation, the young parasites 

 would become fully developed, would produce young in 

 large quantities, and would inflict upon the digester of human 

 tissue, pains and grievances compared with which the pro- 

 verbial troubles which afflict the just are as nothing. 



Less to be dreaded than the trichina, but more extra- 

 ordinary in its habits, is the " Guinea-worm," a well-known 

 parasite, confined in its distribution to certain portions of 

 Arabia, to the banks of the Ganges, and to Abyssinia and 

 the Guinea coast. From the latter locality the organism 



