PARASITES THAT ABE FREE WHEN OLD. 181 



organs are developed, that many naturalists have taken 

 these worms for a simple ovisac. This has also heen 

 the case with the Nematobothrium of the fish known 

 under the name, of the eagle-fish ; it has been taken by 

 an eminent naturalist for a nest of psorospermise. 



There are also worms which take refuge in plants, 

 and live at their expense, as if they were in an insect. 

 One of the most remarkable is that which attacks corn, 

 and produces the disease known by the name of smut, 

 the corn eel (AnguilluUna tritici.) It is a very small 

 and thin cylindrical worm, which dries up completely 

 with the grain of corn which has nourished it, and which 

 can remain for an indefinite period without dying, in a 

 state resembling dust. Every time that it is moistened, 

 it resumes its activity. This return to life has been 

 compared to a kind of resurrection. 



Mons. Davaine has studied this worm with great care ; 

 he has made known the different phases of its develop- 

 ment, and the manner in which it introduces itself into 

 the plant and the grain. Needham, in his " New Dis- 

 coveries made with the Microscope," (1747) gives a whole 

 chapter to these microscopic eels. 



The larvae of the Anguillula scandens are dried in 

 the galls inhabited by the mother. As soon as these 

 galls fall and grow moist, the larvae revive, and abandon 

 their cradle to live in freedom. Soon after this, they go 

 in search of their plant, take it by storm, and penetrate 

 into the tissues before the period of fecundation ; having 

 become sexual in the interval, these microscopic nema- 

 todes lay their eggs in a nest formed at the expense of 

 the plant. 



Another species lives in the dipsacus, in which also 



