It is admitted by nearly all who have studied the laws which govern the vegetable and animal kingdom that variability is the universal rule. If I say nearly, it is because a very eminent horticultural writer, whom I esteem, has written recently that reproduction is the rule and variation an exception. But in support of his opinion he has not quoted one example, nor explained why there are not two grains of sand of the same size or the same weight; why there are never two leaves of the same tree identically alike, nor two seeds of the same pod producing two plants in every respect the same; why we never meet two twins resembling perfectly. Time and reflection, and particularly observation, will, it is to be hoped, settle this question for the interest of science and progress.

I have been myself for a long while in error. I attributed the variations obtained from seed to the interference of insects, and thought that when rambling in flowers they carried the pollen from one variety to another, and thus produced crossings. But my friend Carriere, editor of the Revue Horticole, of Paris, made me perceive my mistake by calling my attention to the natural law of variation.

I felt very much obliged, but as a free thinker in all matters, and believing only what is demonstrated by irrefragable facts, I searched for proofs and addicted myself particularly to study roses, and I soon perceived that nearly always the natural fecundation takes place before the expansion of the flower buds, and that consequently the intervention of insects was of no avail. What makes me desirous to call the attention of rose growers to this subject is, that notwithstanding its evidence, the law of variability is not generally perceived, principally in horticulture, and because it is in the vegetable kingdom, that there is the largest field for study. Is it not variation that produces all the pleasures in expectation by the hopes we entertain of obtaining something new by sowing?

It is chiefly in the rose tribe that variation has, without our intervention, given us so much delight, by the numerous and beautiful varieties obtained since the beginning of this century.

This natural result has induced some rosarians, amongst which we must cite Henry Bennett, to apply themselves to artificial fecundation, an art which is yet in its infancy, and often ill-practiced, but which will certainly lead to marvels, by judicious selections. A natural fact of variability which has often been produced, and generally passed unnoticed, is dimorphism, commonly called sport or accident. Why a sport? Why an accident? Because the law which has produced them is yet unknown.

Some say that those variations are produced by an unhealthy state, others by over-culture. I suspect them all to be in error, and tell them " seek and you will find."

In the rose tribe some very remarkable sports have sprung up recently - Mabel Morrison, White Baroness and Merville de Lyon, all three with white flowers, issued from Baronne de Rothschild, which has pink flowers.

Tea American Banner, with striped flowers, issued from Tea Bon Silene, and very different in habit from the type; and lately Peter Henderson wrote to me that he had found a dimorphism of Tea Perle des Jardins with the color of Tea Madame Falcot; and it is very likely that very often such reports have occurred without being noticed, and will occur again; and I therefore engage (and it is why I write these lines) all the rosarians, and particularly amateurs, who have more leisure, to pay attention to the slightest deviation they perceive, and to endeavor to fix it by budding or grafting.

[Few good observers of nature have any doubt in these days that the principle of variation exists in nature independently of seminal influence. In Germantown there are several generations of the English oak, all from one single parent tree, which show as many variations as could be found in a wood in Europe. M. De Candolle has recently called the attention of European scientists to this fact in the proceedings of a learned society in Geneva. - Ed. G. M.]