HORTICULTURAL JOURNAL. 165 



for the last few years getting as strong and as vigorous as it was before that 

 period. The Potato disease of 1846 when it attacked a crop, made a whole 

 field of their haulms or "vines" black and rotten, in three days from the 

 period of attack, and the Potato tubers wholly rotten in a week from that 

 date. The next season the "vines" were weaker, and the potatoes smaller, 

 and some of them rotted in the ground ; but nothing like what they did the 

 year previous. The year succeeding this, the vines were scarcely affected 

 anywhere, and the "rot" in the tubers was confined to a few localities. So 

 it has continued improving, till at the present time the " vines" are as 

 strong, the potatoes on the average as large, and where care is bestowed on 

 their culture, the crops are as heavy as in any other period of the plant's 

 history. Still we have the same kinds in general culture as we had previ- 

 ously to 1846, and continued by the same mode of propagation. The fact 

 is, the Potato has been subject to numerous diseases ever since its introduc- 

 tion to cultivation. These have one after another disappeared, succeeded 

 by new forms. 



Five and twenty years ago, the " curl" was the great disease of the day. 

 As soon as the shoot was fairly above ground, it became curled and bushy, 

 and was familiarly called "nose headed." When it had reached this state, 

 there was an end of the crop for that season. Strange enough, the theory 

 of the degeneracy of varieties was then started to account for it ; and old 

 Marshall (not our Humphrey Marshall) advocated this view of the Potato 

 .disease, or " curl," with great energy. But the same mode of propagation 

 was generally continued notwithstanding; and yet in time the " curl" went 

 its way as the first great epidemic has done. 



Well, what are the causes of the Potato diseases, many and numerous ? 

 Atmospheric influences are continually affecting injuriously both plants and 

 animals — exotics readily, but indigenous objects less easily. Some few 

 years ago the G-aillardia was carried off entirely through France. In 

 1842, according to " Flora Cestrica," the common St. Johnswort disap- 

 peared throughout the whole of Pennsylvania. For several years past, the 

 American White Ash has had its leaves blistered and apparently scorched 

 off, regularly the second or third week in June, for miles around Philadel- 

 phia ; and the American Buttonwood, not only its leaves, but young shoots 

 also. 



Foreign Grapes and Gooseberries so readily mildew, that they are prover- 

 bial on that account ; and many other cultivated plants are as well known 

 liable to many disorders. The Potato is no exception. Like all other 

 plants its structure is adapted to certain atmospheric conditions, in the 



