HARDWICKE'S SCIENCE- GOSSIP. 



249 



washing of the eyes as to the holy water ; but in 

 some cases the waters seem to have medical pro- 

 perties. Some holy wells are natural, others arti- 

 ficial holes in a rock that are said never to go dry ; 



Fig. 157. Leac-na-Poule, co. Mayo. 



others are springs. The latter may have a small 

 structure built arouud or over them, while others 

 are left iu their natural state. Usually there is a 

 tree or bush iu their vicinity, and sometimes a 

 cross. The latter generally has been moved from 



Fig. 158. Tober mickle, Dungeagan, Kallinakilligs, co. Kerry. 



some adjacent burial-ground, but sometimes it has 

 been erected by a devotee. The accompanying 

 sketch is of a unique holy well near Ballinskilligs, 

 county Kerry (fig. 15S). The structure over the well 

 would be very like some of the small round cloghans 

 if its height were less or its diameter greater. It is 

 called Tober mickle or St. Michael's Well. 



THE RESTING SPORES OF THE POTATO 



EUNGUS. 



By Wokthixgtox G. Smith, E.L.S. 



[We take the first opportunity of layina: before our readers 

 the following important paper, by Mr. Worthington Smith, 

 from the Monthly Microicopicul Journal for September. — 

 Ed. S.G.] 



THE potato disease in this country is rarely seen 

 before the mouth of July, but this year I re- 

 ceived some infected leaves for examination from 



the editors of the Journal of Horticulture at the be- 

 ginning of June, and my reply to the correspondent 

 was printed on June 10th. The leaves were badly 

 diseased, and I detected the Peronospora in very 

 small quantities here and there, emerging from the 

 breathing pores. This was a week or ten days 

 before Mr. Berkeley brought the matter before the 

 Scientific Committee of the Royal Horticultural 

 Society; and when I heard Mr. Berkeley's remarks 

 about the Protomyces, I immediately accused my- 

 self of great carelessness in possibly overlooking it ; 

 but I was equally certain of the presence of the Pero- 

 nospora in the specimens I examined. 



On receiving authentic specimens of diseased 

 plants from Mr. Barron, of Chiswick, the brown 

 spots on the potato leaves at once reminded me of 

 the figures of some species of Protomyces, and the 

 dimensions agreed tolerably well with some de- 

 scribed plants of that genus ; but the spots, when 

 seen under a high power, appeared very unlike any 

 fungus, and they were very sparingly mixed with 

 other bodies much smaller in diameter, and with 

 a greater external resemblance to true fungus 

 spores. These latter spore-like bodies were of two 

 sizes— one transparent and of exactly the same size 

 as the cells of the leaf (and therefore very easily 

 overlooked), and the other darker, possibly reticu- 

 lated, and smaller. A few mycelial threads might 

 be seen winding amongst the cellular tissue, and 

 these threads led me to the conclusion that the 

 thickened and discoloured spots ou the leaves were 

 caused by the corrosive action of the mycelium, in 

 the same way as peach, almond, walnut, and other 

 leaves are thickened, blistered, and discoloured by 

 the spawn of the Ascomyces, as illustrated at the 

 last meeting of the Royal Horticultural Society. 



My opinion, therefore, was soon formed that the 

 "new" potato disease (as it has been called) was 

 no other than the old enemy in disguise, or, in other 

 words, that it was the old Peronospora infestans in 

 an unusual and excited condition. That climatic 

 conditions had thrown the growth of this fungus 

 forward and out of season was probable; but the 

 idea that the pest would not at length attack all and 

 every sort of potato was to me most unreasonable, 

 though the more tender sorts might be the first 

 to suffer. 



Suspecting the two-sized small bodies before 

 mentioned to be of the nature of spores, and remem- 

 bering my experiments during last autumn with 

 ketchup, in which I observed that the spores of the 

 common mushroom might be boiled several times, 

 and for lengthened periods, without their collapsing 

 or bursting, I thought I would try to set free the 

 presumed spores in the potato leaves by macerating 

 the foliage, stems, and tubers in cold water. This 

 maceration was necessary because the tissue of the 

 diseased leaves was so opaque and corroded, and the 

 cell-walls were so thickened, that it was difficult to 



