De Vries : Mutation Theory (1909)
Van Mons' Pears

One of the most frequently discussed questions in practical horticulture is that of the origin of fruit trees, especially of the modern improved kinds of apples and pears. There is no doubt about the common origin of these forms. The question is only whether their common origin merely follows from the theory of descent or whether it is historically traceable. The latter is certainly not the case with most of the chief types; the past history is only known with certainty in the case of some of the recent sorts.

2The literature on this subject seems to be little known and is difficult to get hold of: I have not succeeded in seeing the works of Poiteau and Chandeze. The following is a list of the most important:
    VAN MONS, Arbres fruitiers ou Pomonomie belge, 2 vols, 1835. Quotations from it will be found in JORDAN'S Arbres fruitiers, pp. 38 and 94.
    POITEAU, Théorie de Van Mons ou notice historiquc sur les moyens qu'emploie Van Mons pour obtenir d'excellents fruits de semis. Ann. Soc. d'Agric., Paris, 1834, Vol. 15.
    G. CHANDÈZE, La Theorie de Van Mons concernant la production de nouvelles  variétés fruitieres. Belgique horticole, 1877, p. 354. Bot. Jahrb., V, p. 761.
    GODRON, De I'Espèce, II, p. 101.
1 Pomonomie, I, p. 445,
2 Loc. cit., p. 406, 444.
3 Loc. cit., p. 410.
4 Loc. cit., II, p. 208.
5 Loc. cit., p. 462 and II, p. 208.
6 Loc. cit., I, p. 415.

It is to the Belgian breeder Van Mons that we owe the most valuable information on this subject that we possess. In the first half of the nineteenth century he put many of our well-known kinds on the market.2

Van Mons expressly stated that he himself had not originated any new forms: "La nature seule crée."1 He found all the sorts which he cultivated and put on the market, growing as such in the wild state2 and, as it happened, almost all of them in the Ardennes. The wild plants were thorny and their fruits small, tough and woody. As the result of being sown in a garden and under the influence of another climate3 they regularly lose their thorns and the tough consistency of their fruits, which become larger, fleshier and juicier. But the differences in form, color and taste and other valuable characters arose neither in, nor as a result of, cultivation; they already existed in the wild forms. His new kinds are nothing more nor less than already well-known cultivated forms4 which he has improved in respect of size and juiciness, by selection for two or three generations5 without altering their varietal characters in the very least.6 Van Mons was fully aware of the independence and constancy of these forms and it should be noted that he speaks of them as subspecies and not as varieties.

The best way to raise a new type for the market is not to sow the seeds of the best sorts already in cultivation but those of a fruit which, be it ever so puny, belongs to a hitherto unknown type.

It seems that most of the new sorts that have been raised by other breeders have arisen in the same way. For example the splendid St. Germain pear owes its origin to a single tree found by chance in the Forêt de St. Germain near Paris; Bézy de Chaumontel, Bergamotte Sylvanche, and Virgouleuse are also due to a lucky find.