THE FLORAL VVOELD AND GARDEN GUIDE. 175 



that sulphur possessed such specific properties, but no one discovered 

 that any material reduced to very fine powder, and which would not 

 injure the plant or its fruit, would equally well cure the disease. 

 When it is spread abundantly on the grape, where it attaches itself 

 easily, it acts, as 1 believe, by its drying the parasitic fungus, ab- 

 sorbing its juices, and thus cutting off its nourishment. la some 

 microscopic observations I have made, I think I have seen this effect 

 produced just at the point where the peduncle of the pai"asitic grains 

 is attached to the grape, and possibly, on the grains themselves. 

 Having observed that those grapes which lay upon the earth were 

 not attacked by the disease, I concluded very naturally that the 

 most efficacious means to cure it was by powdering the plant with 

 earth. 



The following experiments led me to consider my discovery as an 

 infallible remedy. I powdered my vines with European sulphur, 

 save one corner of my vineyard apart from the rest, which was saved 

 for experiment. This was divided into two portions ; one was 

 treated with sulphurous earth of Kalamaki, called " antirusty " 

 (antigaleuse), the other simply with clay, leaving, at the same time, 

 a few vines in their natural state, to see if the disease might not 

 cease spontaneously. In due time, the three portions treated with 

 European sulphur, earth of Kalamaki, and with clay, alike showed 

 the cure desired, while the vines not treated at all were entirely 

 destroyed by the disease. Therefore, I concluded that pulverized 

 earth merited equal confidence with sulphur. As some persons sup- 

 pose that sulphur exercises an influence at some considerable distance, 

 I repeated the experiment the following year in a part of my vine- 

 yard distant from where sulphur was used, and not forgetting to leave 

 some vines without any treatment. Three months later, the vines 

 not powdered were destroyed, while those treated with argillaceous 

 earth were saved, convincing me fully that such argillaceous earth 

 radically cured the disease. Yet I resolved to continue the experi- 

 ments during 1858, and test the following matters : — 



1st. If, in order to save expense and labour, two powderings 

 would not suffice instead of three ? 



2ud. What is the best time to make the applications ? 

 3rd. If, having omitted the first application, it would be possible 

 to efiect it by a later application ? 



In order to settle these three questions, I performed the follow- 

 ing experiments : I powdered a number of vines before flowering, 

 and twice later, at the times when sulphur is usually applied. The 

 cure was complete. Fifteen days after I commenced the preceding 

 experiments, I commenced another series in the same way. Nine 

 days had not passed before signs of the disease appeared, when I 

 immediately repeated the application of pulverized earth, and had 

 the satisfaction to see the disease arrested. I repeated the experi- 

 ment the third and fourth time with the same results. Another 

 series was powdered at the time of the setting or formation of the 

 young grapes, but without success, although the earth was used 

 abundantly. A fourth lot was left untouched in the midst of the 

 rest, which was like the last attacked. 



