USE OF ETHER AND CHLOROFORM FOR FORCING SHRUBS. 47 



at present uninformed, but it would probably be nil. Under the cover of 

 the box is suspended a small containing vessel into which the ether is 

 poured through a hole in the top, which is at once hermetically closed, 

 and the plants are then left to themselves. This position of the con- 

 taining vessel is very important, as the vapour of ether being heavier 

 than the air, it gravitates towards the bottom of the box, whereas it could 

 not act on the higher branches if the containing vessel were placed at a 

 lower level. Naturally this work is done in the day time, and away from 

 any flame, as the vapour of ether is very inflammable and produces, in 

 contact with the air, a mixture the explosion of which would be disastrous, 

 and as terrible as that of firedamp. It is as well, then, never to approach 

 the box with a lamp or even a cigar, and the heating apparatus should be 

 at some distance. Thirty or forty grammes * of ether are enough for a 

 hundred cubic litres t of air. and the time the plants are kept in the box 

 is about forty- eight hours. This time, as well as the dose of ether, may 

 be varied according to circumstances and the nature of the plants 

 operated on : it may be advantageous to etherise them for forty-eight hours, 

 then expcse them to the air for forty-eight hours, and then treat them 

 with ether again for forty-eight hours. The ether to be used is pure 

 sulphuric ether, which boils at 35 3 C. (95° F.) 



Immediately after this treatment the plants should be placed in a cold 

 house, where they are treated in the usual manner. It is not very 

 unusual for the buds to begin to push in the ether chamber. In every 

 -case the forcing will be more rapid, and require less heat, than under 

 normal conditions. It was thus that Dr. Johannsen caused Lilacs 

 that had been etherised in the first week in August to flower regularly 

 during the first fortnight in September. With other shrubs, such as 

 Azalea mollis, Viburnum Opulus, Primus triloba, Deutzia gracilis, and 

 some of the Spiraeas; the results were more or less favourable.? 



After the experiments of Dr. Johannsen had been put into actual 

 practice by Danish gardeners, they were closely followed by certain German 

 florists. In 1899 Mons. H. Seyderhelm, a horticulturist at Hamburg, went 

 to Copenhagen for the purpose of learning by ocular demonstration the 

 method made use of by the Danish savant, and wrote to him the year 

 after : "I am now convinced that ycur discovery for the fcrcing of flowers 

 and shrubs is one of great importance to practical floriculture." § 



Mons. Franz Ledieu, Inspector of the Dresden Botanical Garden, has 

 described in the German paper Gartcnflora, and afterwards in the French 

 he Jardin, some experiments made under his direction at the trial station 

 of that garden. He says : " For early forcing the action of ether is of 

 such importance that the great firms of shrub forcers will be obliged to 

 introduce this method of cultivation. Flowers produced by early forcing, 

 coming at a time when they are in great demand, find buyers at high 

 prices. It should be remembered, moreover, that the economy of fuel 

 realised by this method (since the forcing can be done at either a high 

 or low temperature) is very marked, and thus covers . the cost of etherisa- 

 tion." || 



* A gramme = almost IH grains. t A litre = 61 cubic inches. 



X Bulletin de la Socie'te' ccntrale d' Horticulture de Nancy, janv., few, 1903. 

 § A. Maumene, Nouvelle Methode de Culture force'e, p. 43. 

 || Le Jardin, 1901. 



