140 



in which last case the deformed roots assunie an aspect reminding one of the 

 normally moniliform root of Spirea filipendula. The whole structure belongs to 

 the endlessly varied gall productions, and it is certainly a very interesting specimen 

 of this group of physiological alterations of the common mode of growth. 



By making with a razor a thin transverse section of a thickened root, and 

 submitting it to microscopical examination. there is rcvealed without difficulty r 

 and by the relatively small magnification of from 50 to 200 diameters, a very curious 

 sight. There we see, as shown in fig. 94, that a great number of small spherical 

 nr somewhat irregular cavities are disseminated through the morbid tissues of 

 the root. The contents enclosed in these cavities are very different, according to 



Fig. 93. — Dibeaseil roots of Gardenia. 



their age, and in one and the same microscopic preparation there may be found 

 in somc of these cavities (the youngest) a protoplasmic mass with minute oil 

 drops, in others a great number of eggs, with or without young worms fully 

 developed; and, in the oldest, a considerable number of these little worms, hat- 

 ched from their eggs, and in active movement. All this will at once be under- 

 stood when it is known that every single cavity is filled with, or rather consists 

 of, a so-called ova-cyst, that is, the strongly swollen portion of the body of a 

 viviparous maternal anima! (see fig. 96/') filled with eggs, in different gradations 

 of development. 



Before entering on the details of the bodily structure of the animal itself 1 

 must direct further attention to fig. 94 and fig. 95, showing sections of a hyper- 

 in >phied root. The roots from which these preparations were taken were rather 

 old, and their primary structure was altered by secondary or cambial growth. 

 Now, it is a remarkable fact that the wood which is the product of this growth 



