22 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



risk of the " weed-killer " destroying not only the weeds but also 

 the grass and choice plants you want to save. 



It is clearly not a philosophical, nor even a defensible, attitude 

 of mind to rail at this inevitable state of affairs : Nature may be 

 circ umvented and ingeniously interfered with — cajoled, if you 

 like— in various ways, but she will surely not be moved by 

 vituperation. 



Experts in microscopic gardening soon showed that in some 

 cases at least success was possible. 



As early as 1858 Kiihn had observed that certain smut fungi 

 (Bunt) obtain access to the seedling owing to their spores 

 adhering to the grain and germinating when it does so, and 

 found that steeping the grain in copper-salts kills these spores 

 without hurting the more resistent grain. The practice of 

 steeping grain has now been carried to such perfection that 

 very little Bunt ever appears now. It is important to notice that 

 the intelligent application of these preventive measures depends 

 entirely on a proper knowledge of the life history of the fungus 

 and its relations to the host-plant, and this knowledge was only 

 obtained by microscopic gardening. But the testing of the new 

 knowledge by experiments in the open must be referred to the 

 grower on a large scale, and we must not forget that only by 

 experiments can these matters be tested. 



But an even earlier application of the knowledge obtained by 

 microscopic observations of parasitic fungi was the recommenda- 

 tion of powdered sulphur scattered over plants affected with 

 mildew, by the late Mr. Berkeley, one of the ablest observers of 

 fungi we have ever had. 



The methods of applying remedial measures to plant-diseases 

 have increased and varied much since those days, and although 

 there is still much to learn, we have learnt much ; but through- 

 out t he long story of accumulating experience the one truth steadily 

 rings— all experiments with fungicides must be planned with due 

 regard to a knowledge of the habits of the fungus and with intelli- 

 gent interest in the behaviour of the host under treatment. The 

 treatment which is efficacious in dealing with " damping off" of 

 seedlings must be varied when we deal with "finger and toe," 

 which Dr. Somc rville and Mr. Massee have shown can be success- 

 fully combated by lime ; and neither procedure will serve with 

 "bunt" or "smut" or with the " potato disease," "vine 



