2G8 



HARDWICKE'S SCIENCE -GOSSIP. 



Fig. 161. The Resting Spore of the Potato Fungus (A) imbedded among 

 the leaf-cells, x 250. 



had its contents differentiated in a necklace-like 

 manner, and gave birth to the zoospores far re- 

 moved from the original vesicles. The same thread 

 also produced two true oogonia on the water. 



4. At the meeting of the Scientific Committee of 

 the Royal Horticultural Society, held on July 21, 

 Mr. Renny showed a species of Saprolegnia which, 

 he said, might be mistaken for Peronospora. But 

 if reference is made to my original paper, it will be 

 seen from the first that I have perceived the in- 

 timate connection between the new condition of the 

 potato fungus and the Saprolegniese. On my side 

 I have the high authority of Thuret and Berkeley 

 for similar alternation in the diseases of silkworms, 



flies, &c. I am quite prepared, therefore, to con- 

 sider Mr. Renny's plant, if not the same, some close 

 ally with mine, even if it should turn out to be a 

 true Pythium, and its oogonia produce zoospores in 

 water, especially after what is known of the nature 

 of Cystopus, the close ally of Peronospora. Two 

 strong points in favour of this view are these : 

 (1) The resting spores of Pythium are miknown, 

 but if I find Pythium inside potato stems and leaves 

 mixed up with the Peronospora, and the same Py- 

 thium in the very centre of the tuber of the potato 

 (as I have done), there maturing itself and forming 

 its resting spore ; then the identity of the two may 

 reasonably be assumed, and the resting spore of the 



