294 DISEASES OF FIELD & GARDEN CROPS. [CH. xxxv. 



comparable with the impregnated ovum, or fertilised seed ; 

 but it unfortunately happened that from 1846 to 1875 no 

 one saw the bodies again as originally described by Messrs. 

 Montagne and Berkeley. This failure may have arisen from 

 bad searching or from searching at the wrong time, or, 

 as we believe, in wrong material, through imperfect know- 

 ledge ; it may partly have arisen from the fact of the 

 oogonia being exactly the same in size with the cells of the 

 potato leaf. Whatever the reason may have been, we at 

 length saw these bodies again in 1875 within the leaves 

 of badly diseased potatoes sent to us from the garden of 

 the Royal Horticultural Society at Chiswick. The sexual 

 organs are illustrated at S, T, U, and V, Fig. 127. As 

 we were, at the time of the discovery, familiar with Mr. 

 Berkeley's writings and views, we instantly perceived, on 

 looking at these growths for the first time, that we had 

 before us the bodies first detected by Dr. Rayer, Chief 

 Physician of the Hopital de la Charite" at Paris ; described 

 by Dr. Monatgne, and referred by Mr. Berkeley to Perono- 

 spora infestans, Mont. 



