328 M. H. V. Mohl on the Structure of Chlorophyll. 



when we cut across the cell in which they lie under water, and 

 thus allow water to enter into the cavity. The bands with which 

 the water comes in contact swell up and push out in an irre- 

 gular manner, in particular portions of variable length, globular 

 or ovate, or if they are long, spirally curled masses. Originally 

 these protrusions are uniformly green, but subsequently, one or 

 more colourless vesicles, composed of a homogeneous mucila- 

 ginous substance and filled with water, break out from them. 

 These vesicles do not originate by the up-lifting, from the green 

 substance, of a membrane lying on the surface of the band, of 

 which indeed no trace can be detected ; on the contrary, it does 

 not admit of doubt that these vesicles break out from the inte- 

 rior of the band, and tear and push aside the green substance, 

 which only expands to a certain extent. Comparison of a great 

 number of these vesicles also leaves no doubt that their number 

 and form, and the place where they originate, is unconnected 

 with the internal organization of the band, but purely accidental. 

 The vesicles break out sometimes in the middle, sometimes in 

 the edge of the band, sometimes push the green substance to 

 one side, sometimes tear it across and push it away to the two 

 ends, where they meet the prolongations of the band ; sometimes 

 only a short piece of the band is transformed into a vesicle, 

 sometimes a long piece, in which lie one to five of the above- 

 mentioned starch-granules. The latter in the meantime un- 

 dergo no further alteration than that the individual granules of 

 which they are composed become more evident, as is always the 

 case when water acts upon chlorophyll which contains starch- 

 granules ; they do not swell up, and are stripped off the vesicles 

 with the green substance. Iodine colours the entire substance 

 of the bands brown, the green mass darker, the vesicles lighter. 

 There cannot be the slightest doubt that the cause of the 

 phsenomena just described lies in an endosmose set up by the 

 internal substance of the chlorophyll-band. At the same time 

 we must note well, that these phsenomena are of essentially dif- 

 ferent kind from those which Goppert and Cohn state that they 

 observed in- the action of water upon chlorophyll-granules. It 

 is evident, namely, that the endosmose is not brought about 

 here by fluid contents mixing with the water that has pene- 

 trated, separated from the water by a membrane, but by a 

 tough substance, not dissolving in water, which has the pro- 

 perty of forming vacuoles when it absorbs water, receiving the 

 water into these vacuoles and thereby producing an endosmose 

 independently, without the cooperation of a separate membrane. 

 The water which penetrates, therefore, does not serve, as re- 

 presented by Goppert and Cohn, to increase the mass of a green- 

 coloured fluid, and to expand a colourless membrane enclosing 



