Heredity and Environment in Originating New Fruits
THOMAS MEEHAN, GERMANTOWN, PA.
Mr. President, and Fellow Members of the American Pomological Society:
Sometime since I received this letter from our worthy Secretary: "Will you kindly consent to give us a paper on Heredity and Environment in Originating New Fruits?" I suppose that to mean that there have been fruits that have originated by reason of the environment, that is to say that on account of some peculiar conditions or circumstances, climatic or otherwise, some of the species have sprung into existence, or some of the varieties have, by reason of those peculiar circumstances and conditions, come into existence, and that is what is called environment.
Now I was a little surprised to receive that invitation, because although scientific men generally have come to the conclusion that not merely. varieties but species have sprung into existence by reason of the environment, and that idea has become so generally diffused through the community that it might be supposed, with the little interest I sometimes show in scientific matters, that I also have an idea of that kind, nevertheless, the more I have thought of the matter, the more I am convinced that environment, so-called, has never had any such influence in originating any variety, much less any species; and I am therefore under the impression that my friend, in notifying me to address you on this occasion, must have done so—as my record is clear on that score—to raise a first-class row and shake the red flag at the bull, and lie by and see where the sport comes in.
It seems certainly contrary to general rule, that a party appointed to open a subject should have to speak on the negative. That is all I can do this afternoon; I can show you some reasons why I believe no species or varieties of any consequence have ever originated in that way. I have given some considerable thought to this, and have looked over the evidence about it not only in the vegetable but in the animal kingdom also, but I cannot see where there is any circumstance or condition for any permanent influence of this kind. Certainly when we look around us in the animal kingdom, we can see no evidence of it whatever. Take these pictures of Indians before us [referring to the Catlin collection hung on the walls of the hall], they will suggest some facts which I think bear very strongly on the subject before us. We have here, men of the Indian race spread over the whole continent, from the Arctic regions to the Gulf of Mexico; men who for centuries have been living under the most varied conditions of environment, and yet they are Indians today; yet, as I said, their conditions have been extremely different. In the far northwest they live in the winter time half buried in the ground, spending a few months in summer fishing, and living all the winter on dried fish and perhaps deer fat. On the prairies of Nebraska we find Pawnees living, as I have seen, almost wholly on animal food obtained in the chase; living as is shown in that picture, number 401 of the collection, in wigwams formed by a few stakes and skins stretched around them for shelter, moving from place to place leading a nomadic and unsettled life, entirely different to those I referred to before in the Northwestern parts of the continent. As we get further along on the South Pacific coast, we find Digger Indians living on herbs and roots, and in entirely different habits and characters from those further northwest; and then again, down further south are the Zunis, whom we find in the past living as an agricultural people, having their canals for irrigation, having houses for protection, and protecting themselves by ladders. Thus, we can see the most varied conditions and environments, and yet everybody knows they are still Indians to-day after thousands of years of those very varied conditions of environment, some living on plains, some on rocky mountains, some in arid deserts, and some where rains and dews and other good things abound. Of course they will sometimes get some little advantage by some discoveries, and there we see the ability that other classes of men have to take advantage of circumstances. As soon as Indians got fire arms, they spread through the whole of the Indian community. When some few years ago they could get horses they seized on them, and wherever they have been able to get the implements of civilization, they have to some extent progressed by means of their use, but they have never so progressed that they are not Indians to-day. I think that is true also of other animals. The horse with the Indian is just. the same after two hundred years of Indian environment, as he is with the environment furnished him by the more civilized white man. Again, the horse itself has been the servant of man through all history, and has been taken into all sorts of climates and subjected to all sorts of conditions. Environment of most varied character has furnished the horses as well as other domestic animals. But we see no difference which we can trace to environment. The different breeds of horses have been the direct work of man by uniting varied conditions, and what is called environment as ordinarily understood, has nothing to do with the various breeds of horses and cattle, but differ as they may they are not different in character from the horses of two or four thousand years ago. And so far as the human race is concerned, I believe—setting aside the Indian and taking for instance, if you choose, the natives of Africa—I believe if they are taken fresh from that soil to day and brought to this continent and remain in Maryland for two thousand years, they would still have essentially the characteristics of the Negro race. And so with the white man taken to Africa; you would still find the distinctions characterizing the race. So I see no reason for believing that environment has had any vital effect in influencing change. It is the same when we look at the plants. I have had an opportunity to examine the different timber trees of our country extending all the way along the mountains from Canada to Mexico, and we find the Linden tree from Mexico precisely the same as we find the Linden tree on the Potomac River and in Canada—no different. It, makes no difference whether those trees grow on plains or mountains, whether under conditions of climate furnished by Mexico or by Canada. Notwithstanding this, there is not the slightest difference whatever between the Linden we find in Mexico, and that which we find in Labrador. So with the Sweet Gum, we find precisely the same tree in Mexico and precisely the same in our own swamps here. I see nowhere any evidence whatever that climatic conditions or anything whatever involved in them, or in the idea of environment has had anything to do in producing new varieties or species. On the contrary, when we find any new forms coming into existence they, simply spring into existence of a sudden without any law with which we are acquainted, without any knowledge as to what has produced those laws. We may have as every nurseryman knows, seedlings of various trees for centuries, and yet all at once a weeping variety is found—as the weeping beech, ash, etc., and whenever they come they spring into existence; environment cannot be understood as having anything to do with bringing them into existence, and the florist continually knows that some of his best varieties are no more than sudden freaks of nature. Some variety springs into existence not merely from the seeds—perhaps sometimes from bud variation. Some variety which has been in cultivation perhaps for twenty or thirty years or more, with its own peculiar color or general characteristics, will push out a branch entirely different from the rest of the plant, and the cultivator can therefrom introduce the new variety. Environment could not possibly have had anything to do with the conditions of the same plant. What is true of flowers now in cultivation by florists, is also true of fruits. The Nectarine was originally a branch from the Peach tree, and we have a class of fruits which spring off of a sudden—apparently of a sudden—certainly without any knowledge of the law that produces them. We have evidence of these things every day. One of our friends pointed out to me this morning a Peach which she had on exhibition, the "Stump the World" Peach, a Peach which ripened its fruit four weeks ago, and yet that particular branch pushing out of a sudden produced another variety which ripened four weeks before the other. There is another illustration where environment has had nothing to do with the case. I, therefore, have been unable to see anywhere around me any evidence in any kingdom that environment has had anything to do with the introduction of new varieties. To be fair to the subject. one point has struck me occasionally as evidencing some little disposition to operate by reason of environment, and that is in the question of hardiness. I think it is generally admitted by all who have studied geology, that at one time what is now the Rocky Mountains was a plain of about the same level with the line which now forms the Western coast of California and Nevada, and the mountains were thrown up by some great eruption of nature, thousands of years after the rest of the Pacific Coast was formed. Whatever trees and vegetation were on the land then were thrown up with it, and the conditions surrounding those trees and plants were greatly changed. Being thrown up from seven or eight to fourteen or fifteen thousand feet high, vegetation must have found itself in an entirely different climate and in entirely different conditions, as it might be said, with an environment of a totally different character than that which surrounded it before the mountains were thrown up. Paleontology shows its that was just the case. Many varieties of oak and the redwood tree which were all growing in the Rocky Mountains at the time this eruption took place could not stand the change of climate, and all we know of them now is by finding their remains in a false condition. But a few managed to get there. What we once called the Colorado Blue Spruce managed to get there. The Douglas Spruce also managed to get there, and two or three other kinds of pines managed to get there notwithstanding the great change in environment. They managed to live and get there, but they have not changed materially in all their characteristics by reason of having been thrown up so high. Pinus ponderosa is the same in the Rocky Mountains to-day as it is on the Pacific Coast. The other one I mentioned—the Douglas Spruce—is the same; with all its changes it has retained the same characteristics. But there is an illustration where plants which have evidently been thrown into greatly changed environment have remained the same except in the one point, of hardiness. When we bring the Douglas Spruce here it is easily killed by comparatively mild winters, but those species from the Rocky Mountains will endure. Again, I have had other illustrations to show that hardiness is an acquired character to some extent. We frequently in nurseries sow seeds in large quantities of certain trees, for instance of the common Sweet Gum tree. If we get the seed from Georgia, as sometimes we do, or from the Carolinas, light winter destroys them, but the seed from Maryland, Delaware or Pennsylvania will never die. Undoubtedly they have acquired hardiness by ages of cultivation in hardier localities. I am satisfied, therefore, that so far as achieving hardiness is concerned, plants may possibly profit by environment so far as that goes, but outside of that., so far as any essential characteristic is concerned, I have never seen any. I know it is sometimes said that if we take a Bartlett Pear, for instance, raised in Pennsylvania, and plant them in Savannah or Charleston or some other place along the seaboard, they do change their character. 1 have heard some people say they could not tell a Bartlett raised under those conditions, from their acquaintance with the Bartlett of Pennsylvania or further North, but I have never failed to detect. what they were, and I think the idea that there is any essential change in these respects is an idea greatly exaggerated. Taken all together, I feel that no variety has been raised worthy of being called a variety simply by the circumstance of environment. When we come to heredity, that is entirely another matter. If we could prove that varieties were induced by environment, the other part of my question would be easy, for undoubtedly heredity has much more power and strength than is generally supposed, as at one time it was thought to be the evidence of a true species if it would reproduce itself from fruit. If it would not do so, it was simply a variety, and that was the test given. But I think we all know now from very wide experience that there is just the same tendency to heredity in a variety however induced, whether from the seed or bud variation—the character of sport which I have already referred to- no matter how casual may seem the circumstances that may have induced the variation, that variation is just as great as if induced in what we call species. Many years ago I raised a large quantity of seeds from the Weeping Beech, which we know to be a variation from the original Beech, and every one of the seedlings was weeping just as the parent was; and so with the Weeping Ash; I have had experience with that, and I think everyone must have bad a similar experience. The purple leafed plants are just the same. The Purple Beech is so true to seed that it is often the practice of nurserymen to raise it in that way. When we come to vegetables we know how it is. A new variety of pea or of bean or of anything else that we raise in our garden crops, when we plant them by themselves and raise seed from them, they are just as true and just as constant as the original species from which they sprung, so that so far as heredity is concerned, there is no doubt in my mind that when we once get possession of a variety, the laws of heredity will prevail to preserve it for us as it would from the original species from which the variety was raised. Not to detain the meeting further, I will say briefly that so far as the matter committed to me is concerned, I have never seen any reason why environment should be considered as being the parent of any variety that we have or are likely to have; while, on the other hand, so far as heredity is concerned, I believe it to be a more powerful agent in preserving to us variations nature has given us than we have before been accustomed to believe.
MR. STRONG: Since the red flag has been shaken in the face of the bull, I have no disposition myself to come in contact with the animal, and yet I feel inclined to say that I think he has stated the case a little too strongly. I think he has carried the point in the main, but has he not also in stating some of the facts shown that there has been some little modification? He has spoken of the increased hardiness of some plants in different localities. I would like to mention one in particular—the Magnolia Glauca, which grows freely in Massachusetts, and is entirely hardy as the seedlings from it are; but the seedlings taken from Florida are entirely tender and worthless with us. I am the more inclined to say a word in reference to a point the speaker made, and as to which. I think he was in the main correct. I wish to state the facts in regard to a recent rose—one introduced within the past. year; I mean the Waban rose. The facts were told to me by Mr. Montgomery, who was the originator of the rose. It is a sport from the Catharine Mermet rose. Mr. Montgomery told me that the plant which had been planted in their conservatory, after two or three years had become an old stunted plant and they were about to throw it away, until he noticed one day that it had produced a large deeper colored rose than the normal type, and it had been in such a state of neglect that he ascribed the change in color to the condition—environment. He preserved the shoots of that rose, noticing it as so marked. He propagated the rose, and it has retained its characteristics. I judge that Mr. Meehan referred to that particular rose in his remarks, and I think the facts as stated by Mr. Montgomery ought to be known, and perhaps Mr. Meehan will have a word to say on that point.
PROFESSOR RILEY: There are other papers this afternoon, and therefore I do not wish to occupy much of your time, but I should be sorry to leave Mr. Meehan's interesting communication without a few words. Mr. Meehan's arguments and presentation of facts have this characteristic of merit, that they are always provocative of discussion and reply. Now the subject of evolution—the subject of variation in form, whether plant or animal, and the influences that bring about that variation in the present as they brought it about in the past—that subject is one that has always deeply interested me; in fact I have written upon it and have discussed the influences which affect specific variation in an address which I had the honor to deliver before the American Association for the Advancement of Science at Cleveland. Now the two factors that Mr. Meehan refers to are almost universally recognized by evolutionists as conservative factors. If Mr. Meehan means to argue that change of environment—change of condition of life does not produce variation, then I say that his position is antagonized by the experience of the majority of most persons whether they be breeders of animals, students of animal or plant life, or students of evolution. For environment is one of the potent factors of the change of form, appearance, character, attitude, appetite—change in fact in a dozen or a hundred different directions. Now this change may not always be perceptible on the individual, though often it is marked there. But it becomes more and more patent in time—in races. The changes Mr. Meehan has referred to are what we know as fortuitous variations, and are all of them referable to that limbo that we call fortuitous, and it was one of Darwin's faults that he failed to recognize fortuitous variation to the extent to which it takes place in nature. But when it comes to changes that are permanent in nature and not artificial—perpetuated by man by artificial means—then I think the store of evidence is overwhelming that environment has played and is playing a most important part in producing variation. Now we must recognize this fortuitous variation. There is variation going on around us all the time under the same conditions, and man simply takes charge of that portion for his own benefit, and perpetuates what nature otherwise would not do. She perpetuates only what is essential to her, and it is the type that is perpetuated by her, whereas the changes, alterations and variations Mr. Meehan refers to are what are known as simply varieties. Many of them would not be perpetuated in a state of nature. I would also say that the law of atavism is as well recognized a law as that of heredity. While heredity is conservative, atavism will produce changes, and the series cited by Mr. Meehan as to the uniformity of his seedlings, will not be borne out by many of you as nurserymen in the very great variation of seedlings generally shown. Seedlings are well known to vary, and these variations are attributed first of all to atavism—to reversion to some earlier parent or to cross fertilization, etc. But this is a very great subject and I do not wish to take the time of the Society. I only wish to put in my plea for the influence of the conditions of life, when they are changed, upon variation, and to rather dissent from the general tenor of our friend's remarks. While I realized that some of the facts he has stated are perfectly justified and correct, the application of them in my judgment is not.
PROFESSOR BAILEY: I do not wish to have these remarks go unchallenged in regard to the purely horticultural side of this question. While Mr. Meehan was giving us his interesting talk, two things occurred to me as perhaps open to objection, one of which has been mentioned by Mr. Riley. I suppose the speaker had in view the matter of change of conditions of life upon the organism. Professor Riley has referred to that. The other weak point, or one other, was this: That in speaking of these variations, he said that when they did occur, they still occurred within the limits of the species. The Indians which occur all about the country are Indians still, he said, and that is true enough, but they are of different tribes. But now from the truly horticultural side I wish to oppose Mr. Meehan's doctrine, because there are innumerable facts against it. I am positive that change of environment or change of conditions of life does modify every type of plant which man has cultivated. I do not believe there is a single plant cultivated from a period of a quarter of a century and from several degrees of latitude, but has changed considerably. To cite instances would be to cite the whole catalogue of plants. Darwin has shown that winter wheat can be changed to spring wheat, and rice versa conditions and environments—as to whether it is planted in spring or fall. The English cucumbers, characterized by their great length and by their ability to produce long fruit entirely without the aid of pollen—fruits entirely seedless and which have larger flowers than ordinary cucumbers, have all been developed in this century by environment, and we have the records so complete that we know that within this century those cucumbers have been produced from the common field cucumbers. Peas have been changed in their characters in one season by the character of the soil upon which they grow, which is one of the conditions of life and of environment, and I have myself in my own patches detected two varieties of peas from one row, one end of which was in heavy soil and one in clayey soil. Others have had the same experience, and every fruit which we grow in some way or other is changed by climate. In the North it becomes smaller and hardier. Go to yonder hail and see the fruits from Minnesota and Wisconsin, and see if their luster is not brighter than that of fruit from latitudes further south. I never saw this so plainly marked as at the meeting of this Society in Grand Rapids on some specimens of Minnesota fruit. It is well known that flowers and fruit take on intenser colors as we go Northward. Environment certainly does change. Cabbages are not the same in the South as they are in the North. So these things change all over the country in an intricate net work, and I do not believe there is one plant under heaven which man has cultivated long which has not been modified greatly by environment.
MR. HALSTED: I wish to say just a word in this connection as to diseases of plants—or fungus diseases of plants. If you were in my laboratory, I could show you fungus diseases of plants grown under different conditions in test tubes; spores from the same plant that when placed under a microscope the mycologist might declare were of different species, and that only takes five days. The difference is environment.
MR. FERNOW: I only want to point out the difficulty we have in discussing such a subject before we have a conception of our ideas regarding the nomenclature. Now we are accustomed to speak of variations and species entirely from a morphological point of view, and I believe there is where the difficulty lies in explaining differences resulting from environment. Mr. Meehan has given one point himself in speaking of the hardiness being changed by environment. We believe that more than that is true of the change in biological features. I know for a fact that in the Caucasian race, and I believe also in our Indian brothers, exists absolute differences not of form but of characteristics, and these characteristics are bred by their surroundings. I am well acquainted with European nations, and well acquainted with the American. Now we know there is considerable difference in the characteristics of the two nations which have been brought about by—I do not know anything else but by surroundings—the differences of climate and the necessary difference of occupation. So I believe that one of the difficulties in talking on this question, is that we misconceive what we should call species and what variation; that we have no biological conception of these terms, and it would be necessary to define just what is meant by species and variation.
MR. MEEHAN: Did I not tell you that your Secretary was getting me into a great racket? Perhaps I may he gored after all, but I must say that so far as the arguments have gone nothing has been advanced to shake the position I assume. Mr. Riley has simply reiterated what I said before. I said the tendency of scientific men was to consider that environment was a great factor. He has simply emphasized that. I do not think that meets any point I have made. Now in regard to what Mr. Bailey has stated with reference to a great many of the statements Darwin has made, I would say that I was familiar with those statements when I made the point I have already made, and although those points seem to have great weight with Mr. Bailey, they have had no weight with me; many evidences go to show that Darwin and his followers have mistaken altogether what they themselves meant by environment. I think what they mean by environment is the operation of some natural law outside the agency of man, and so far as that is concerned I have seen no great evidence to show that any great change has ever occurred in that way.
MR. FERNOW interposed, that in discussing this important biological question it was only too frequently overlooked that in speaking of species and varieties we refer to these as established by morphological distinctions. Such distinctions may satisfy the systematician, but the biologist will have to find biological distinction, and as our knowledge of these increases, our conceptions of species and varieties will change. We will then have species and varieties based upon biological characters, rather than morphological distinctions. Thus while zoologically speaking there is no specific distinction between the European and American, yet there were such marked differences in character evidently produced in differences in environment as should distinguish them specifically. The same would he found among the Indian tribes which Mr. Meehan cited as specifically the same.