18 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



higher levels of the soil — which reminds us that earthworms, 

 like slugs, ground-beetles, and other relatively large soil-animals, 

 are active, if unconscious, microscopic under-gardeners, whose 

 actions profoundly affect the distribution of the various soil 

 organisms. But here I must stop, or the mere recital of the 

 little that has yet been accomplished, judging from its com- 

 parison with the indications of what is coming in day by day, 

 will carry me beyond the scope of a lecture to a trial of your 

 patience, for which I have no desire to incur responsibility. 



The first record I can find of microscopic gardening which 

 applies to the culture of parasitic fungi, is due to an Englishman 

 named Marshall, who in 1782 tested the belief that barberry 

 bushes were in some way responsible for the rust of wheat, and 

 found that the wheat was rusted in proportion to its proximity 

 to the plants. 



It is true Marshall knew nothing of the nature of the fungus, 

 and that his experiment can at best be compared to one where 

 we prepare a bed near some w T eeds and see what will come ; but 

 I think this Norfolk gentleman should have his memory credited 

 with the honour due to a scientific idea, for it was a scientific 

 experiment in agriculture on a microscopic scale. 



Willdenow in 1804 went a step further, and streaked the 

 yellow spores of the barberry fungus on the leaves of a grass 

 and some other plants ; and Hornemann in 1814 dusted the 

 spores on leaves of wheat, rye, and other cereals. Gmelin had 

 named the fungus on the barberry in 1786, and Persoon those 

 on the wheat in 1797 to 1801, but it is evident that no clear ideas 

 as to their nature were then possible, and we must look upon the 

 experiments as not so much definite attempts to grow microscopic, 

 plants, as rather the exposure of the selected seed-beds (the 

 leaves) to mysterious influences to see what would come. In 

 most cases nothing came ; but in 1810 Scholer, and in 1818 

 BOnninghansen, did infect grass leaves by dusting them with the 

 barberry rust. 



In 1804 we meet with a very different case when De Bary 

 not only aowed the spores of wheat rust on the barberry, and 

 obtained a crop of barberry rust, but he observed the germina- 

 tion of the spores and ingrowth of the fungus on the leaves 

 thciiKclves. De Bary had already in 1801 observed the entrance 

 of the germ-tube of PJiytophlhora into the potato plant— the 



