1011 



later (wlicn the loss hv Iraiispiralioii ol llic boiiglis li;ul risen to IVom G 

 to 10" '(, of their oriij;iiial weigiit) reached a maximum and then 

 declined again. 



Bonghs of Plnis mains and Populiis nigra which were investigated 

 in the same way at tlie same time as those of Viscum showed no 

 simihxr phenomena; the intensity of tianspiration was here verj 

 great and remained almost nnchanged imtil the bonghs had dried 

 np. In an experiment conducted some days later in precisely the 

 same way with some evei'greens [Hedera lieiiv, Pinus spec, Abies 

 spec, etc.) transpiration was at first also great, but gradually declined 

 nntil a minimum was reached. Therefore these evergreens showed 

 nothing of the irregularity which was. noticed in Viscum. 



The ready conclusion that in the expeiiment with Viscum it was 

 not a question of one or another disturbing factor, which had been 

 overlooked, bnt probably of some physiological peculiarity due to 

 the structure of the slomata, was further confirmed by the fact that 

 on looking through the protocols of my experiments I found again 

 very clearly the same irregularity in an experiment conducted in 

 Brazil with Rhipsalis Cassytha. The structure of the stomata of this 

 plant agrees in sexeral very obvious characteristics with those of 

 Viscum album. 



For the experiment, of which I give here the results only so far 

 as they bear upon the phenomenon in question, a large |)lant was 

 carefully loosened from the tree on which it grew, and hung up in 

 the laboratory. The weight of this plant was recorded at intervals 

 for a period of 136 days. 



The following diminution in weight was observed : 



during the first 



,, „ second 



„ third 



,, fourth 



ith 



H^'' and 7''' 



„ 8"^ and 9^i' 



,, 10^'' and 11"' 



„ 12"Uo 16"' inclusive 



„ 17"' „28"^ 



„ 29"' ._, 37"^ 



„ 38"' „ 76"' 



„ 77"' „ 104"' 



„ 105"^, 136"' „ 



24 hours 1,36 "/„ 



2,10 «/„ 



2,13 V„ 



1,77 7„ 



on the average 0,94 7o 

 „ „ „ 0,9047„ 



,. „ „ 0,86 »/„ 



1 01 7 



„ ,, ,, 0,88 7o 



,, „ „ 0,68 7„ 



„ „ „ 0,42 7« 



), ), )i 0,2o /j 





O 



