EAU CELESTE. 



263 



first be placed the results of the comparative trials made with cupric 

 anticryptogamics not endowed with this property, such as bouillie 

 bordelaise and bouillie bourguignonne. They do not establish practically 

 the sporicidal superiority of eau celeste. Millardet and Gayon ob- 

 tained the following results : — 



TABLE LL — Showing the Effect of SpraytTig Vines with Eau Celeste, on the 

 Density of the Wort, the Weight of the Wort per Kilogramme of Grapes, 

 the Sugar Content per Litre of the Wort, and the Weight of the Grapes. 



Secondly, highly dilute solutions of these cupric compounds do not 

 dissolve cellulose unless after long maceration, and moreover, thirdly, 

 the organic matter of which the cells of fungi consist is not cellulose, 

 but an analogous substance which has not the same reactions as 

 cellulose. Even if it be admitted that the liquor of Bellot des Minieres 

 can dissolve spores in contact with the solution, the method of applica- 

 tion is against these properties being exercised. Sprayings, in fact, 

 spread a thin layer of this liquor on the surface of the leaves ; the 

 ammonia evaporates forthwith, and there remains on the leaves in- 

 soluble cupric hydrate, with no solvent action on cellulose. The 

 solvent action of this liquor only lasts a very short time, which would 

 enable it to act curatively at the moment it is projected on to the 

 diseased organs. The application of these preparations in the full 

 evolution of mildew has produced immediate curative effects, which 

 would plead in favour of a special action of which bouillie bordelaise 

 and bouillie bourguignonne are deprived, but it is known that blue 

 vitriol solutions exercise to the same extent a curative action on this 

 disease. Solutions of copper hydrate in ammonia or in other alkalies 

 have quite peculiar properties. Thus Bellot des Minieres' preparation 

 of a certain strength, like eau celeste modifiee, dissolves cellulose, and 

 a solution of 5 parts of blue vitriol in 100 parts of water, added to 

 5 parts of glycerin and a sufficiency of caustic potash to redissolve the 

 precipitate first formed and give an azure solution, possesses the re- 

 markable property of dissolving natural silk. From there to the con- 

 clusion that this preparation should be the most perfect insecticide is 

 but a step, since it can dissolve the shell of the insect, the composition 

 of which is very analogous to that of silk. This insecticide, which has 

 not yet been tested in actual practice, would only decompose very 

 slowly, and might act energetically on insects. [Mouillefert has found 



