STRUCTURE OF CHLOROPHYLL BODIES. 53 



noticeable if the preparation is previously treated with potash, 

 which causes the starch grains to swell. This last method also 

 enables the smallest quantity of starch in the chlorophyll bodies 

 to be recognised ; but the result is even more certain if the 

 chlorophyll grains are treated with a solution of five parts of 

 chloral hydrate in two parts of water to which a little iodine 

 solution has been added on the object-slide. The chlorophyll 

 is dissolved, so that in a few minutes the leaf appears colourless ; 

 simultaneously the chlorophyll body swells, and also the starch 

 grains which it contains, and these last come out clearly with 

 the blue colour. Leaves decolorised with alcohol show also very 

 beautifully, with the same treatment, the blue-stained starch 

 grains in the chlorophyll bodies, while these last are not stained. 

 After the chlorophyll bodies have been decolorised by alcohol 

 they can be stained also very well with very dilute watery 

 solution of methyl violet or of gentiana. violet. The cell mem- 

 branes also are coloured, but the chlorophyll bodies more deeply, 

 and therefore stand out more sharply. Rosaniline violet also is 

 an excellent stain. 



With stronger magnification the living chlorophyll bodies of 

 the leaf of Funaria appear to be finely porous ; this can also be 

 seen in other chlorophyll bodies, such as those of Vallisneria, and 

 very well indeed in Crassulaceous plants of the common culti- 

 vated genus Echeveria, in the uninjured cells of the lower 

 mesophyll cut parallel to the surface. 



The same results as with leaves of Funaria are obtained with 

 prothallia of ferns, so that the two objects can replace one 

 another. Prothallia are always readily to be found in plant 

 houses in which ferns are cultivated ; and any species can be 

 used. 



Change of Position of Chlorophyll Grains. The same moss 

 Funaria, or Mnium, can be used for the purpose of a physio- 

 logical demonstration under the microscope, to the effect that the 

 position of the chlorophyll bodies in the cells is subject to the 

 influence of light. Both of these plants are very sensitive to 

 light, and the leaves can be examined entire. Plants which have 

 for a considerable time been exposed to diffused daylight show 

 the chlorophyll bodies collected on the upper and under surfaces 

 of the leaf-cells (position of Epistrophe) ; if removed into a dark 

 room, or placed under an opaque shade, usually a few hours, but 

 sometimes one only, suffices to show the chlorophyll bodies re- 



