C'liAi'. XXXI.] LILACS OF rilK I'AIMS (JARDENS. iViO 



developed, and wliicli therefore remain white. According to M. 

 Lavallee, specimens of the artificial white Lilac were first exhibited 

 to the Society by M. Laurent in 1860. These specimens excited 

 a great deal of interest and surprise amongst the members of the 

 Society at the time, and a commission was appointed to investigate 

 the means by which M. Laurent succeeded in obtaining such 

 beautiful results. M. Laurent's mode of procedure was found to 

 be very simple. It consisted in forcing the plants in a hothouse 

 heated to 80" Fahr., and kept in a perfect state of darkness. M. 

 Laurent, however, allowed that it was not impossible now and 

 then to obtain white flowers on plants grown in broad daylight. 



At the same time the commission reported on the results ob- 

 tained by another Paris grower, M. Berthelot, who, also engaged 

 in forcing Lilacs, produced the same eff'ect in the full light of day, 

 using for the purpose a well-lighted house, heated to a high 

 temperature. From this fact M, Duchartre, who acted as 

 reporter to the commission, concluded that heat as well as absence 

 of light was capable of preventing the formation of the colouring- 

 matter in the petals of the Lilac. M. Lavallee has thoroughly 

 tested both these totally-different methods of arriving at the same 

 result, and has succeeded in obtaining perfectly-white flowers in 

 both cases. He is decidedly of opinion, however, that white 

 Lilacs, grown in an ordinary well-lighted house, give thicker and 

 larger bunches of flowers, and which last a longer time than when 

 M. Laurent's method is employed, and finally, that the open- 

 daylight mode of culture requires much less care and attention. 

 Some 9 ft. or 10 ft. of a frame in a Dutch greenhouse were 

 devoted by M. Lavallee to this experiment, the Lilac-plants being 

 planted so that their buds were within from 8 in. to 1 ft. of the 

 glass. They were then left to themselves for nearly three weeks, 

 the house being kept at a temperature of from 68'' to I"/". At the 

 end of tliis time the Marly Lilac was in full bloom, while the 

 Charles X. variety did not blossom until four or live days after. 

 It has been stated that the last-named beautiful variety could not 

 be forced, but ]\[. Lavallee has proved this to be a mistake. It 

 seems, however, that in the early part of the season it does not 

 always come to perfection, the plants placed in the forcing-house 

 by M. Lavallee in November having failed to flower ; but after the 

 beginning of Decemlier it is the best variety for forcing. Two 



