SYNCHYTRIUM 



101 



ciliate zoospores, 3-4 fi in diameter in some instances, 

 escaped directly into the water of the hanging-drop, whereas 

 in other instances, the inner hyaline wall of the resting- 





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Fig. 21. Synchytrivm solani. 1, section through portion 

 of a young potato sprout, showing many of the peripheral 

 cells infected by the zoospores of the fungus. The central cell 

 that is dividing has escaped infection ; 2, section through a 

 portion of a scab, showing mature resting-spores deep down 

 in the tissue and the youngest at the periphery ; 3, a 

 young resting-spore not yet enclosed in a thick wall ; 4, 5, 

 and 7, mature resting-spores ; 6, a resting-spore germinat- 

 ing, i-ciliate. zoospores escaping. All highly mng. 



spore, containing the zoospores, was extruded, the zoospores 

 eventually escaping into the water. The epidermal cells are 

 infected by the zoospore, which at first forms a naked mass 

 of protoplasm that gradually increases in size, then becomes 

 invested with a thin, colourless wall, upon which is eventually 

 laid down a thick, brown, smooth, stratified, chitinous wall. 



