50 LEAVES FROM AN APRIL JOURNAL. 



From the cracked bark high up on these birches 

 oozes the exuberant sap that drops on the dead 

 leaves beneath like the drippings of rain after a 

 shower. 



What is this mysterious power that sends the 

 juices rushing up through countless tubes into 

 every extremity of these living creatures? We 

 listen in vain for the heart-throb within their 

 wooden breasts, yet life blood flows silently through 

 the arteries and veins, making new wood and liber. 

 The heart indeed is inactive, but if our ears were 

 sufficiently acute, we could catch the sounds of 

 the working of many machines under ground sup- 

 plying the porous roots with water, acids and 

 earthy salts, which being properly mixed with 

 sugar, mucilage, and protoplasm contained in the 

 root, forms the true sap. This engine is called 

 endosmose. But the force which causes the circu- 

 lation in every branch and twig, is not a pusliing 

 one from below, but a lifting one, many millions 

 of miles above us, indeed, the great source of light 

 and life, the sun. Even from the tips of those 

 buds the moisture in invisible streams, drawn 

 upward into the air, leaving behind certain organic 

 matter in the leaves, and the sap in them being 

 denser, soaks up the thinner fluid in the cells 



