No. 4. 



The Petatoe Disease. 



109 



to show that it was caused by some atmos- 

 pheric influence ; but the contrary was the 

 case. In some fields it appeared as early 

 as July, even on adjoining farms. The 

 cause then remains still a mystery. 



Of remedies, a very great number had 

 been suggested; many without due conside- 

 ration. 



The commissiouers sent by the English 

 government into Ireland, were particularly 

 unfortunate in this respect for want of a 

 little practical knowledge added to tlieir un- 

 doubted scientific attainments. All the 

 means of prevention that have formerly 

 proved successful, failed during the last 

 year. An excellent method has been to 

 change the seed every year, taking it from 

 .a high country to the lowlands, but this was 

 found to have lost its efiicacy. Gypsum and 

 hot slaked lime, have also been of little bene- 

 fit. The greening of potatoes intended for 

 seed, by letting them lay in the sun, has 

 been much recommended, and on cutting up 

 the sun-burned potatoes, it has been found, 

 according to some statements, that the 

 greened parts were never diseased. It may 

 be well to turn attention to this subject. In 

 former years some persons succeeded in in- 

 vigorating the crop by means of certain sa- 

 line manures, and even during the last sea- 

 son it was thought that they were in some 

 degree beneficial. We are not aware that 

 any plan heretofore suggested, has proved 

 uniformly successful over any great breadth 

 of country. 



The preservation of the crop during the 

 winter has excited the deepest interest, and 

 here also the number of methods proposed 

 defies enumeration. The result of all the 

 trials seems to be that the disease makes 

 very slow progress, and in many instances 

 none at all, when the potatoes are kept 

 perfectly dry and well ventilated. Both of 

 these conditions seem absolutely essential; 

 packing them in dry absorbent earth, and 

 even in charcoal, has proved a signal fail- 

 ure. It is necessary in any case where the 

 disease has made much progress to pick over 

 the heaps frequently, and carefully select 

 all of the affected tubers. Kiln-drying has 

 been resorted to in cases of extremity; this 

 preserves the potatoe for food, but of course 

 destroys its vitality. 



Of the various plans proposed for the 

 planting of potatoes in spring, none has 

 been found more efficacious than cutting 

 carefully selected potatoes into sets, con- 

 taining each two or three healthy eyes. 

 These sets are sprinkled with sulphuric or 

 hydrochloric acid, diluted in the proportion 

 of one pound of acid to four gallons of wa- 

 ter. Newly slaked lime, or gypsum, is then 



added so as to form a crust over the cut sur- 

 face. 



The diseased potatoes have not been found 

 injurious as food. In Scotland all kinds of 

 domestic animals have been fed with them 

 freely, and actually thrived upon them. We 

 have, in the present communication, glanced 

 merely at the principal points of interest 

 hitherto touched, in the researches upon this 

 subject; it is much to know which are false 

 theories, even if we have made little posi- 

 tive advance. 



Prof Johnson, in a late communication, 

 has informed us that from attentive conside- 

 ration of the analyses of diseased and healthy 

 potatoes made in his laboratory during the 

 past year, he has been led to recommend 

 the application of a certain manure to the 

 potatoe crop, as calculated, in many cases if 

 not universally, to arrest the disease. He 

 does not speak of this with confidence, but 

 as a thing yet to be tried. The publication 

 containing his paper has not yet reached us, 

 and we are consequently unable to say 

 more. 



We are forced to conclude that the origin 

 and causes of this disease are at present un- 

 known; its mysterious marks have appeared 

 suddenly on two continents, separated by 

 two oceans; under the heat and drought, 

 rain and cold, on wet and dry, light and 

 heavy soils, at every elevation, and in every 

 variety of potatoe. Those who have most 

 carefully investigated its peculiarities, most 

 widely examined its range, are most unde- 

 cided as to its cause. 



Only by a very long and extended series 

 of experiments, by an accumulation of ac- 

 curate results, can we hope to arrive at a 

 solution of the mysterious problem. No 

 subject of the present day offers more at- 

 tractions to the scientific man, or a wider 

 field of usefulness. The very existence of 

 a crop of incalculable importance seems at 

 stake; practice has entirely failed in its 

 efforts to 'correct the evil, and looks to sci- 

 ence for that aid, which, if within the limits 

 of possibility, should be afforded. — Silliman^s 

 Journal of Science and Arts. 



New Material for Shingles. — A patent 

 for a new invention has been obtained by Mr. 

 William Beach, of Troy, for the application 

 and mode of using cast-iron plates for cover- 

 ing roofs. "They are about one foot square, 

 and made to fit into another, so as to render 

 the roof water tight, by applying white lead 

 to the joints. It can be afforded at sixteen 

 cents the square foot, and comes at about half 

 the cost of copper. They weigh 3^ pounds 

 a square foot." It is easily attached to the 

 roof, and promises to be of much utility. 



