8 Elementary Botany 



young cell is at first made up. It is very complex in its chemical 

 constitution, but always contains nitrogen. Iodine colours it 

 brown, and concentrated sulphuric acid rose-red; whilst it is also 

 stained by magenta. It is soft and jelly-like in consistency, 

 never truly fluid. At times it is homogeneous and transparent] 

 more often it is granular. It forms the vital portion of the cell, 

 and possesses considerable power of movement. It readily 

 absorbs water, which, however, forms drops or vacuoles in its 

 interior. 



The movements of protoplasm may be grouped under two 

 heads : — 



1, Movements of protoplasmic masses destitute of a cell 

 wall. 



{a) Swimming by means of cilia, as in the case of Proto- 

 coccus (p. i). 



{b) Amoebiform movements, where a naked mass of proto- 

 plasm emits irregular'projections {pseudopodid) at various parts 

 of its surface ; the rest of the mass ilowing after the processes. 

 This is seen in the remarkable animal the Amoeba, or Proteus 

 animalcule, and is met with in some of the lower forms of plant 

 life. 



2. Movements of protoplasm within the cell wall. 



In many cases the protoplasm contained within the cellu- 

 lose wall shows a tendency to rotate or circulate in various 

 directions through the cell, often carrying with it substances 

 which may be imbedded in it. This is especially well seen in 

 the cells of many water plants. (See fig. 19.) 



Chlorophyll is the substance to whose presence the green 

 colour of plants is due. It occurs (in the higher plants) in the 

 form of granules imbedded in the protoplasm of various parts 

 of the plant. These granules really consist of two parts — a 

 colourless more or less solid portion, which is formed out of 

 the protoplasm and builds up the chlorophyll granules ; and a 

 green colouring matter diifused through and colouring it. The 

 exact chemical composition is not yet known, but there appear 

 to be two separate colouring matters, the one yellow, phyllox- 

 anthin, and the other blue, phyllocyanin, which by their union 

 give the green tint. 



