November 3, 1906 



HORTICULTURE 



46» 



Functions of the Bacteria and Origin of Species 



Editor HoRTicuLTUiiE. 



My dear Sir: — I have two quotations to present to 

 yon, wliich are very interesting to me and seem worthy 

 of consideration on the part of horticulturists. The 

 first is in Prof. Hilgard's book entitled "Soils" and 

 constitutes tlie third paragraph of page 145. The sec- 

 ond is taken from the inaugural address of Prof. E. 

 Ray Lankester, president of the British Association for 

 the Advancement of Science and was delivered at the 

 August meeting of that body in York. The whole 

 address has been printed in various publications, I 

 make my excerpt from Science for August 24th, 1906, 

 page 228: 



"Functions of the Bacteria. — While there is still much 

 uncertainty as to the exact functions performed by most 

 of these bacteria in respect to soil-formation and plant 

 growth, there are several kinds whose activity has been 

 proved to be of the utmost importance in one or both 

 directions, it having been shown that when the soil is 

 sterilized either by heat or antiseptic agents, certain 

 essential processes are completely suppressed until the 

 soil is re-infected and the conditions of bacterial life 

 restored." 



"The observations of de Vries — showing that in culti- 

 vated varieties of plants a new form will sometimes assert 

 itself suddenly and attain a certain period of dominance, 

 though not having been gradually brought into existence 

 by a slow process of selection — have been considered by 



him and by a good many naturalists, as indicating the 

 way in which new species arise in nature. This sugges- 

 tion is a valuable one if not very novel, but a good deal 

 of observation will have to be made before it can be 

 admitted as really having a wide bearing upon the origin 

 of species. The same is true of those interesting observa- 

 tions which were first made by Mendel, and have been 

 resuscitated and extended with great labor and ingenuity 

 by recent workers, especially in this country by Bateson 

 and his pupils. If it should prove to be true that varieties 

 when crossed do not, in the course of eventual interbreed- 

 ing, produce intermediate forms as hybrids, but that char- 

 acters are either dominant or recessive, and that breeds 

 result having pure unmixed characters — we should, in pro- 

 portion as the Mendelian law is shown to apply to all tis- 

 sues and organs and to a majority of organisms, have 

 before us a very important and determining principle, in 

 all that relates to heredity and variation. It remains, 

 however, to be shown how far the Mendelian phenome- 

 non is general. And it is, of course, admitted on all sides 

 that, even were the Mendelian phenomenon general and 

 raised to the rank of a law of heredity, it would not be 

 subversive of Mr. Darwin's generalizations, but probably 

 tend to the more ready application of them to the explana- 

 tion of many difficult cases of tbe structure and distribu- 

 tion of organisms." 



Very sincerely yours. 



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Tiox AND Cross-bhi;i:ding, August 2, 1906 

 Tli€ President, Sir Trevor Lawrence in the Chair. 



