8 Proceedings of the Royal Irish Academy. 



period of over three weeks elapses before the first signs of disease become 

 apparent in inoculated stalks. It seems fairly certain, therefore, that — at least 

 in the erperiment named — some canse other than B. pliytopMTwrus must have 

 been at work. 



In 1906 Appel(7) described an entirely different bacterial disease of the 

 potato, to which he gave the name " Eingki-ankheit." The name is derived 

 from the fact that attacked tubers when cut open fi-equently show the 

 " vascular ring " as a brown line running parallel to the skin of the tuber. 

 The rot which arises in the tuber is one which proceeds fi'om within out- 

 wards. Affected sets usually produce no plants at all, or but feeble ones 

 which soon die after coming above ground. Bacteria of several nearly allied 

 varieties are put down as the cause of the disease ; but up to the present no 

 extended description of them has been published, our knowledge of the disease 

 being chiefly confined to that published in popular leaflet form only. The 

 disease would seem to belong, as far as external appearances go, to that group 

 of maladies which had hitherto been aggregated together imder the genei-al 

 name of " Krauselkrankheit " (cuiI). A fuller study of this disease and of 

 the bacteria causing it is at present a desideratum. So far as we are aware it 

 does not exist in this country ; for, although a look-out has been kept for it for 

 a considerable period, it has so far not come before our notice. In India, how- 

 ever, Coleman (8) has published a more or less populai' report on a disease of 

 this character, known locally as " BangadL" A more extensive and scientific 

 paper on the subject is akeady promised by this author, fi'om which, 

 doubtless, our knowledge of this disease and its cause will be considerably 

 extended. 



The latest account of a serious bacterial disease of the potato hails from 

 Canada. Hai-rison (18) described, iu 1906, a disease which was paiticularly 

 troublesome during the two previous years in the province of Ontario. The 

 symptoms were, he states, ia many respects similar to those of " Sehwarzbeiu- 

 igkeit," ia Germany, but different from the bacterial diseases in France 

 described by Prillieux and Delacroix. Plants here and there among the rows 

 present a sickly appearance, with di'ooping, somewhat yellow or discoloured 

 leaves. The stems gradually fall until they rest upon the groxmd, and 

 ultimately the stems and leaves shrivel up. The stems are usually blackened 

 near the ground, and sometimes also fiuther up. The tubers also show the 

 disease in a characteristic way. Hanison isolated fi'om the affected plants 

 a hitherto undescribed micro-organism, which he called Bacillus solanisa,prus, 

 and proved most conclusively that this organism was the cause of the disease. 

 It is a rod-shaped form of variable length, actively motile, and possessing 

 from-five to fifteen flagella. In beef-peptone-gelatiae stab cultures liquefaction 



