63 



with the fluid ; remains fixed in the smallest ramifica- 

 tions; and, 



a. Becomes further developed in the vascular tube, 

 making use of the walls of the vessel as an envelope 

 (cyst), so as to remain there permanently ; or, 



p. Migrates passively into the neighboring tissues, 

 after the rupture of the walls of the vessels, in con- 

 sequence of the swelling of the body of the embryo ; 

 or, 



7. After sticking in the finest vascular ramifications, 

 enters anew upon an active migration by means of its 

 six small booklets, passing through the walls of the 

 vessels into the neighboring tissues, and often con- 

 tinuing its wanderings for some time in closed cavi- 

 ties, or in the soft parenchyma of organs, even when 

 it has attained to a certain size, so as to be visible to 

 the naked eye (Kiichenmeister). 



Having reached, by these wanderings, the suitable 

 spot for its further development, we then notice that 

 the embryo becomes stationary ; and frequently we are 

 able to track it by streaks of a yellowish color, which 

 are produced in the organ by exudative inflammation, 

 caused by these journeyings. This exudation some- 

 times also occurs round the embryo itself, enclosing it 

 in a capsule, and excluding it from the organism : this 

 process has been described by Yon Siebold (" Ueber 

 die Band-und Blasenwiirmer "), under the name of the 

 " extrinsic encysting process." When this extrinsic 

 encysting process does not take place, the embryo 

 begins to enlarge and swell up from the fluid nutri- 

 ment which it receives from the tissues where it is 



