no THE PHYSIOLOGY OF PLANTS 



colourless, but is impregnated with the green colouring matter 

 termed chlorophyll, which is soluble in alcohol. Sometimes 

 there are only a few chlorophyll grains in each cell ; generally, 

 however, they are pretty numerous (sometimes more than 30), 

 and they lie imbedded in the semi-fluid layer of protoplasm 

 which lines the inside of each cell-wall, and is termed primordial 

 utricle. In some cells of the leaf, which have a large lumen, a 

 movement of this protoplasmic lining will be noticeable, carry- 

 ing with it the chlorophyll granules. By this means they are 

 able to wander in each cell towards the point which is best 

 supplied with air and light. During the day they place them- 

 selves near the upper surface of the cells, and in the angles 

 which adjoin the air-containing intercellular spaces (position of 

 epistrophe), while at night they move towards the inner walls 

 which adjoin other cells {apostrophe). 



§ 20. How are assimilating cells of the leaf protected ? 



As we see that without chlorophyll granules a cell is not 

 able to form any new organic matter, we must come to the 

 conclusion that the most important and essential formative 

 body in the vegetable kingdom is the chlorophyll grain. 



We are therefore completely justified in saying that "with- 

 out ehlorophyll there can be no organic life." For, as a matter 

 of fact, the existence of animal organisms is dependent upon 

 the presence of vegetable organisms. Carnivorous animals 

 feed exclusively upon herbivorous animals, and the food of 

 the latter, the products of the vegetable kingdom, depend 

 upon the activity of the chlorophyll grain. The objection 

 which might be raised, that the Fungi represent a large group 

 of plants which may produce a considerable amount of matter 

 without possessing any chlorophyll, does not hold good, for Fungi 

 can only live on organic substances. If the latter still, form part 

 of a living organism, we are dealing with a parasitic Fungi ; 

 but if the substance is no longer connected with a living 

 organism, and is in process of decomposition, we term the 

 Fungi saprophytic. In either case, the substance is of an 

 organic nature, and consequently the result (direct or indirect) 

 of the activity of the chlorophyll. 



