" 5th. Since it is very probable tbat the seed- 

 tubercles that may escape from the present croj) 

 will be infected with the germ of the mushroom, 

 it would be well if by the intervention of the 

 Government or commerce the farmers had at their 

 disposal pure seed-tubercles, that were not in- 

 fected ; and for this purpose, the Potatoes of 

 Pennsylvania or Ireland would suit us exceed- 

 ingly well. The plague is not known in those 

 two countries. W^e must distrust the Potatoes of 

 Germany, where the dry gangrene, the shrivel- 

 ing [la crixpure) and the ulceration of the tuber- 

 cle is but too common ; and we might take ad- 

 vantage of this importation to endow the coun- 

 try with those varieties of Potatoes which are 

 most congenial to our soil. 



"Cth. If the farmers are obstinate in employ- 

 ing, as seed, tubercles of this year's crop, it will 

 be necessary to subject them to liming, as is done 

 with wheat, rj-e, oats, and all plants which are 

 subject to be invaded by parasites. The liming 

 ought to be done by immersing the tubercles, 

 because the .study of the habits of the ' botrydis' 

 shows it is the ej-e, the deepest point of the Po- 

 tato, which is attacked. The limed vpater should 

 then bathe this leprous eye. 25 kilog. of lime, 

 I lb. of the sulphate of copper, and 3 kilog. of 

 marine salt, to 125 litres of water, constitute a 

 liming of which theu.seful effects have been ac- 

 knowledged by a great number of instructed 

 cultivators. 



• " 7th. In the plantations, either of the winter 

 of 1845 or the spring of 1846, it is essential to 

 plant, in Potatoes, parcels of ground as distant 

 as possible from those infected this year, for it 

 is ea.sily understood that the chance of transmis- 

 Bion, by the preservation, in the soil, of the seed 

 of the mushroom, is much greater in plantings 

 that approach each other than if they were made 

 at a distance. 



•' 8th. When the Counselor de Martens vi.sited 

 Belgium, and inquired in our diffrrcnt prov- 

 inces the state of our Potatoes, he informed me, 

 in one of his interesting conversations, that the 

 farmerson the borders of the Rhinehad remarked 

 that the dry gangrene attacked oftener tlie 

 Potato plantations made in the aftenioon, than 

 those made in the morning ; and he e.xplained 

 this phenomenon, which at first appeared .singu- 

 lar, by a very simple fact When the sun has 

 passed the meridian, the heat of the strata of air 

 is at its maximum: this heat accelerates the vi- 

 talitj' of plants ; that which propagates them flies 

 n>ore rapidly in a diluted air; die insects, in 

 their flight, disperse with facility a mass of little 

 bodies, of which the air is the vehicle ; and the 

 dissemination of their germs is then also at its 

 maximum. The farmer is plunged in this atmo- 

 sphere, and he causes to pass through it the Po- 

 tatoes which he plants ; it attaches it8<;lf to the 

 seed, and is sown with it -, and that happens here 



(son 



which occurs to the grain not limed — the poison 

 is sown and grows with the plant, to attack and 

 kill it at a later period. From which arises the 

 advice we give to the fanners, to plant their Po- 

 tatoes in the morning. 



"9th. The employment of lime and marine 

 salt, mixed with a small quantity of the sulphate 

 of copper, is, as I have said, of a recognized effi- 

 cacy in the destruction of the germs of parasite 

 plants ; consequently, to po^^•der with these 

 mixed sub.stances the soil which has been plant- 

 ed with sick Potatoes, is an operation calculated 

 to destroy the germ of the scourge, and cannot 

 be too strongly recommended everywhere. 



" 10th. The preservation of the Potatoes that 

 have escaped being attacked this year, in cel- 

 lars, &c. will certainly deposit in these places 

 the germ of the mu.shroom. To cleanse these 

 cellars and whitewash them with lime are excel- 

 lent means of destroying the germs, and to 

 spread lime and pounded coal on the places 

 where the Potatoes have been deposited, will 

 finish the series of proceedings we consider the 

 most rational and the most certain to destroy, if 

 it be possible, the evil at its root. 



[Signed] "CH. MORREN, 



" Member of the Royal Academy of Sciences, 

 and Professor of Agriculture and F.conomy 

 ' Ibrcetiere ' at the University of Liege." 



Since the receipt of the above we have been 

 favored with a copy of the following. To the 

 American readers of this joui-nal it is supei-flu- 

 ous to say that Mr. Gowen's zeal, intelligence, 

 close attention and success as a practical farmer, 

 entitle his judgment to high respect, and well 

 account for the British Consul's application to 

 him for the result of his observations on this im- 

 portant subject. 



Correapondcncfi. helween Mr. Peter, British 

 Consul at Philadelphia, and Mr. Gowen. of 

 Moil nl Airy, o/i the subject of the Potato Rot. 



MR. GOWEN'S REPLY. 



Mt. Airy, 29th Dec. 184.";. 



Ml/ Dear Sir : Your note on the subject of 

 " the Potato Rot," dated Saturday, did not reach 

 me at Mount Airj% Sunday intervening, till this 

 morning, Monday. It would give nie pleasure 

 to oblige you fidly in this matter, did time per- 

 mit to go more into detail ; but the brief space 

 allotted for a reply will compel me to be as con- 

 cise as po.'ssible. 



I hold that atmospheric influcnco is the sole 

 cause of the late pervading Rot in the Potato; 

 that neither manures nor condition of soils 

 could have produced the calamity ; that animal- 

 culm and fungi are as remote from it — the latter 

 may in a partial manner injure a Potato plant, as 

 they would, under peculiar circumstances, be 

 likely to injure other plants ; that the Rot /.'! not 

 epidemic ; and have reason to believe that 

 Bonnd or partially sotuid Potatoes, taken from 



