REPORT OF THE SOCIETY 59 



after a deep study of the fatal fungus was born the Bordeaux Mixture of which 

 lie became the zealous and incessant propagator. 



No one is ignorant that copper is the preservative, the active element of 

 this mixture; it acts as preservative agent by creating on the surface 

 of the exterior organs of the plants a deleterious medium to the development of 

 the organisms of mildew. We cannot, in all justice, attribute to Millardet 

 the merit of this discovery. In 1807, in a note on the rust of cereals, Benedict 

 Prevost, pointed out the unfavorable action of sulphate of copper on the germs 

 of rust, and recommended very weak solutions, namelj^ 1 part of sulphate of 

 copper to 400,000 parts of water. While ver^- remarkable for the time, the note 

 of Benedict Prevost had no sequence. 



The appearance of mildew of the vine, well known in the United States 

 since 1824, was to again give it value. Planchon, to whom a monument is 

 erected at Montpellier, in the valley of the Garonne, first discovered the 

 disease. 



Several j'ears elapsed before the anticrj-ptogamic specific was adapted and 

 propagated. It was during this period of groping that Millardet, aided by 

 eminent collaborators like U. Gayon, in the laboratory, and M. Bouisset in 

 the vineyards fixed the proportion of the various ingredients entering into the 

 composition of the cupric mixture, now called Bordeaux mixture, from the place 

 of its origin. The wine-growers commenced to employ this preservative in 

 1885 and ]\Iillardet did not spare his efforts to facilitate the rapid extension 

 of the treatment against mildew. 



It may be easily imagined that the foi'mula now known only became such 

 after numerous alterations. The first formulas proposed contained a conside- 

 rable quantity of sulphate of copper. Millardet himself advised 15% of lime 

 and 8% of copper; others even went up to 12% of salts of copper. Thick mix- 

 tures were the result (which well merited the name of mixture), difficult to 

 spread. The actual formulas for ordinary treatment do not exceed 2%- of 

 sulphate of copper. 



Millardet has also explained the action of Bordeaux mixture on mildew of 

 the vine, by suggesting that the cupric solution acts on the spores of certain 

 cryptogamia that it comes into contract with by preventing their germination. 

 This theory applies as well to several other diseases, as may be judged bj- the 

 popularity Bordeaux mixture has had for nearly fortj- years. There are 

 hardly any horticultural pi'oducts for which the use of this fungicide is not 

 recommended as a preservative from numerous diseases. Of course the action 

 of the preparation is not the same towards all of these parasites; but the unani- 

 mity of the phytopathologists in its favor is an evident proof of its intrinsic 

 merits. 



In Canada, professor Craig was one of the first, if not the first horticulturist 

 to make use of Bordeaux mixture and to recommend its use, about 1895. It 

 has made its wa}^ since then and is still largely in use throughout the whole 

 country, principally for potatoes and other vegetables. 



