I see by your June number that in America as in England a belief exists that the potato disease is caused by Peronospora infestans and not that the fungus is the effect of disease. This, the first cause, had done its deadly work. Then the Peronospora as one of nature's scavengers, clears away the dead matter. On the same principle the worms eat a dead body. Men of science still contend that from 1845 down this fungus is the sole cause; though practical and experimental men are against them; and all the successful experiments that have been brought to bear in endeavoring to cope with the disease militate against them also. I should like to ask where the Peronospora was previous to 1845, and how it existed? It certainly did not exist on rotten potatoes for there were but few about; and also how the vast mass of Peronospora that were in existence the first ten years of the disease live now, and upon what do they feed since natural remedies have been so effectually employed, not to destroy the Peronospora, but to restore the potato and to give the fungi no further work to do? Where are they now? If fungi be the cause of the disease, they certainly must be "blind to their best interests" in not now making further attacks upon the delicious morsels that are all around them and are much more abundant than in 1845. No, it is the carrion they want, and not the potato in its healthy state.

It was not the Peronospora that we had to contend with in the early times of the disease, but the constitutional weakness of the potato which threatened its destruction. The men who have been looking through the microscope have done nothing toward the alleviation of the distress; but the sympathizing practical men fought with debility and snatched the potato from entire destruction.

Much has been written from time to time about the wearing out of races and I suppose it is a doctrine which few will deny, for all nature is hastening to decay; even the world itself is getting older. It is also an admitted fact that you may prolong , or cut short the existence of animal or vegetable life by the way it is treated; and it will not appear at all wonderful to the thoughtful mind, on looking back to the history of the potato and its treatment during the last quarter of a century of its existence before it succumbed to the disease, that it certainly could not much longer bear the immense strain upon its constitution to which it was then being subjected; in the shape of gross feeding; its high cultivation; its unnatural treatment; and all the greed of the exacting cultivator with his determination to have the "last pound of flesh." Even the quality of the sets that were then used for planting for the next season's crop, must have produced the mischief in time if nothing else had accompanied it.

Men who lived in those days will not fail to remember the exhausted state of the sets that were used; how the spears which were the very vitals of the potato were run out and matted together, and the poor potato reduced down to a skeleton and made to appear like pieces of dried sponge, instead of plump healthy sets. Surely those who can remember these things must confess that man and not "the worm" was the cause. I venture to affirm that if we were to treat any other like kind of vegetable that is propagated by the bulb or tuber, such as the tulip, the hvacinth, or the narciss, pretty similar results would follow. In fact, all vegetables and animals when pressure is put upon them like it was upon the poor potato, must, " like riding a free horse to death," finally succumb to its treatment; for all ought to be impressed with the important lesson that if we break nature's laws, we certainly shall sooner or later have to pay the penalty.

It is now generally conceded that Americans and the English have had their labors richly rewarded, for by careful fertilization combined with patience and perseverance we have produced a new and stronger race, which is not only more impervious to the disease, but, as a rule, is far ahead of the old worn-out sorts - both in quality and productiveness - for where would you find in 1840 such splendid sorts as the Beauty of Hebron and the White Elephant? - sorts not confining their merits to one part of the season in particular, but to every part, - and sorts too, that will always reward the cultivator, both for quality and productiveness, - besides the many other fine sorts that follow hard after them, sufficient in number and variety to suit the different soils, and the different countries wherever the potato is grown.

This indomitable perseverance of the two nations has left the Peronospora infestans very little to feed upon, and has almost chased it out of existence so far as the dead potatoes are concerned. How different is it now to the first ten years of the disease. In good seasons it was bad enough, but in ungenial seasons, when the disease was hastened by inclement weather, the crops were scarcely worth digging, and when dug the tissue was so vitiated by traces of the disease, that it was rarely worth eating. But what a marvellous revolution thirty years have produced ! and all this time the poor Peronospora must have been sadly beaten back, and terribly put about for want of its favorite food.

I am pleased to find that my observations are in perfect accord with the essay read before the American Society of Florists, and which appeard in the Gardeners' Monthly for June 1886, page 169. The first observations of the essayest contain the gist of the whole matter. He says : "very few plants are attacked by insects or disease when in vigorous health, it is only when the vitality is impaired, or the growth checked by any cause, that they strike." So that it is only sensible and right that we should blame the real cause of the mischief.

I have always been thankful that I spent some years of the best part of my life in writing and lecturing on this important subject, and battling the various errors that prevented the public from arriving at the real cause of this disease, thus adding my mite to the enlightenment of the public mind in reference to it; so that at the present moment I am more than rewarded by seeing the cultivators of the root all moving on in the right direction, and all taking care of the seed tubers. Planting at suitable times and in suitable soil, and striving to preserve its health and vitality, - not taxing them to their utmost limits - and treating them more in accordance with their natural habits; and striving still, by adhering to natural laws to obtain a more vigorous and healthy progeny. I am exceedingly pleased to find that our united efforts have been crowned with abundant success.

How difficult would it be now in this time of comparatively healthy potatoes to find the Peronospora, or even its resting spores in any quantity? But if once more, through maltreatment, we were to again break up the constitution of the potato and cause it to become debilitated and diseased, we should soon find the fungus in sufficient quantity to carry on the sanitary work as heretofore, " for wheresoever the carcass is, there will the eagles be gathered together".

Ryde, Isle of Wight, England. [The Editor may be pardoned for saying in regard to this communication, that it comes from one who, without any capital but intelligence and good judgment, has become one of the best known, in his own country, among successful nurserymen. Near, if not perhaps on the grounds of which he had charge in 1845, the potato disease made its first terrible appearance in Europe, and possibly no one gave the disease a more careful study from a practical point of view, than C. D. Every one at that time predicted the total disappearance of the potato from cultivation. C. D. was then an enthusiast in his views that utter indifference to the quality of the seed potatoes - sprouting them in the cellars and planting the shrivelled pieces called sets, which had thus to make a new start with sprouts in life, had much to do with disease, - and contending that when we should come to have more common sense views of preserving seed potatoes, potatoes would be as abundant as ever again.

Now, when he must have passed his three score and ten, it is no wonder that he feels a glow of satisfaction, that his advice has been followed, and his pleasant predictions have come to pass. - Ed. G. M].