10 BOTANY. [CHAP. i. 



water and examined under the microscope with a suffi- 

 ciently high magnifying power, numerous minute green 

 balls will be seen of various sizes and presenting different 

 appearances. If we select one of medium size that is 

 perfectly spherical and without any lines on its surface, 

 it will at first resemble a minute green ball, and appear 

 devoid of structure. If a small quantity of hydrate of 

 potash is now mixed with the water, in a very short time 

 a thin colourless ring will appear encircling the green 

 ball ; the colourless ring is the cell-wall or protective 

 portion of the plant that has been rendered visible by 

 the hydrate of potash, and forms a continuous outer 

 pellicle or skin inclosing and protecting the living por- 

 tion of the plant the protoplasm along with the green 

 colouring matter or chlorophyll. A plant presenting the 

 appearance described above is in the vegetative condi- 

 tion, that is, simply doing the work requisite for its own 

 individual well-being, taking into its substance carbonic 

 dioxide and water, which its chlorophyll, under the influ- 

 ence of light, converts chemically into its own substance ; 

 and at the same time breathing for the same purpose 

 that animals do, the removal of carbon from the body in 

 the form of carbonic dioxide. After passing some time 

 in the vegetative phase, the second or reproductive 

 phase, for the object of continuing the same kind of 

 plant, or species, in time is entered upon. Amongst 

 the specimens under the microscope it will not be diffi- 

 cult to select an individual yet perfectly spherical but 

 with a dark line across the surface ; such an individual 

 illustrates the first condition of the second or reproduc- 

 tive phase, the dark line corresponds to a thin wall that 

 has grown completely across the protoplasm, thus 



