ii8 GLIMPSES OF NATURE. 



is the layer, near the bark, through which the sap 

 ascends. 



Now, this fluid forms what botanists call the 

 " crude" sap. It is on its way, in other words, to 

 become perfected in the leaves of the apple-tree. Once 

 in the leaves of its own proper maker, the sap would 

 acquire all the properties which fit it for the nourish- 

 ment of the plant. Why, then, does the mistletoe 

 select the imperfect sap of its host, in place of drawing 

 from the tissues of its prey the perfect material ? 



The answer to this question brings us back to that 

 remark of mine wherein I declared that a redeeming 

 feature existed in the constitution of the mistletoe 

 bough. Our parasite has not passed quite to the 

 depths of life's degradation after all. It still harbours 

 a habit of independent food-making which constitutes 

 a saving clause in its moral character. 



For the crude sap which it absorbs by aid of its 

 roots passes into the mistletoe's own frame, and there 

 undergoes a further elaboration. Into its leaves pass 

 the undigested products of the apple-tree's work, and 

 in the leaves the stolen sap is made fit for nourishing 

 the parasite's own blossoms, and for developing the 

 berries and seeds which are to lay the foundations of 

 the new mistletoe race. 



The green leaves of our parasite also teach us that 

 it may and does do something more in the work of 

 food-making. Green leaves always mean a power of 

 absorbing from the air the carbonic acid gas which 

 forms part of the food of every green plant. Your 

 colourless mushroom will have none of this gas ; it is 

 a more dainty feeder, and demands something of the 

 animal dietary. Mistletoe, perchance, is on the way 

 to lower things. 



