IN THE MOTOR OBGANS OF LEAVES. 



9 



and silvery grey over the intervening areas; the lower ono dull red at the margins 

 and pale green with red veins centrally. Within half an hour very conspicuous changes 

 in colour had occurred, the green originally present in some parts having almost entirely 

 disappeared and been replaced by diffuse dull red and grey; and the tissues had at the 

 same time partially collapsed, owing to commencing ilaccidity. Three hours after the 

 beginning of the experiment the leaf was quite flaccid, the tissues throughout being 



translucent and evidently soaked with fluid. A mere trace of firo exudation had, 

 however, occurred, so that the loss in weight amounted to only •HU grammes. The 

 disappearance of the green colour originally present in some parts of the suifaco was 

 no doubt partly due to yellowing of the chlorophyll under the influence of the changes 

 in the tissue incident on the action of the chloroform vapour; but to a much greater 

 extent to the escape and general diffusion of the red colouring matter normally limited 

 to the interior of the cells in certain areas of the inferior surface. 



Experiment II. — A leaf of Begonia Iiernandae/olia was set in a chloroform-chamber. 

 The leaves in this species are uniformly dull green above and dull red beneath. The 

 leaf very rapidly became flaccid, and at the same time the upper surface became difiusedly 

 reddened, due to escape of the coloured fluid from the o* lis of the lower surface and its 

 general diffusion through the intercellular spaces. 



Experiment III. — A leaf of Begonia rex, coloured like that entploved in the first 

 experiment, was set in a chloroform-chamber. "Within one quarter of an hour the margins 

 of the upper surface had begun to redden, and shortly afterwards the entire surfaco 

 gradually became diffusedly red, the leaf at the same time becoming flaccid and collapsed. 

 As in the previous experiments, the entire tissue became translucent and soaked and the 

 surfaces moist, but there was no massive discharge of liquid. 



Experiment IV. — A leaf of Begonia rex, coloured like the former ones, was set in an 

 alcohol chamber. Within twenty minutes traces of reddening appeared in patches on the 

 margins of the upper surface, and at the close of an hour the whole of the upper surface 

 was irregularly blotched with patches of reddish and pale emerald green. On the 

 following day the leaf was moist, translucent, red at the margins and centre, and reddish 

 green in the intermediate, originally grey, area of the upper surface. The colouring was 

 alike throughout the entire thickness of the lamina. Flaccidity did not set in so rapidly 

 or become so highly developed as in the cases in which chloroform was employed, the 

 differences in this respect and in coloration being no doubt due to the fact that whilst 

 chloroform has no affinity for water and no appreciable solvent power for chlorophyll, 

 alcohol is highly endowed with such properties, so that under its influence we have 

 both diffusion of the chlorophyll green and less accumulation of water in the tissues 

 o-enerally. The red colour of the cell-sap in these cases is apparently unaffected by the 

 changes accompanying anaesthesia, a phenomenon contrasting strongly with what we 

 find occurring in the case of the colour of red petaline tissues under similar circum- 

 stances and no doubt connected with the high permanent acidity of the fluid. 



Whilst the changes occurring in the living elements of the tissues under the influence 

 of anaesthetics lead to a diminution in their retentive power for fluids, and a consequent 

 loss of turgidity, the water-conducting power of the dead elements of the wood remains 



Ann. Roy. Bar. Gard. Calcutta Vol. VI 



