ENTOZOA IN THE AREGLAH TISSUE. 207 



of Africa, where it is endemic, and occasionally 

 epidemic. Its frequent occurrence upon the coast of 

 Guinea has originated the common English name. 



It is a very slender, round worm, of almost uni- 

 form dimensions throughout its whole extent ; and 

 varies from a few inches to four or five feet in length. 

 It attacks the superficial portions of the lower 

 extremities, and it is also sometimes to be met with 

 in the subcutaneous areolar tissue of the body, of the 

 upper extremities, and, in very rare instances, of 

 different parts of the head and face. It is not con- 

 tained witliin a cyst, but fives in a free state in the 

 tissues, and finds its way readily beneath the skin, 

 and between the vessels, nerves, and muscles, or 

 even into the substance of the latter. It is often 

 sohtary, but several filarise may exist simultaneously 

 or successively in the same individual. 



The conditions upon which the appearance and 

 the propagation of the Guinea-worm appear most to 

 depend are moisture and the excessive heat of the 

 co\m tries in which this entozoon prevails ; and the 

 united influence of these causes serves to explain the 

 greater relative frequency of the F. Medinensis at 

 some seasons of the year than at others. 



The filaria which is developed in the human body 

 shows signs of life for a short period only after its 

 extraction, and soon perishes ; so that it evidently does 

 not possess in itself the means of transmission and 

 of propagation. At the time when this entozoon has 

 completed its development, and is ready to leave the 

 organism in which its development has taken place, 

 its body is found to be filled with a milky-looking 

 substance, which, upon microscopic examination, may 



