HUMUS 29 



of vegetable matter not living leaves and grass, but the dead 

 and dying vegetable matter that lies upon the ground. Holding 

 fast in their burrows by the tail-end, the worms reach out in all 

 directions, stretching themselves to great lengths and grasping 

 bits of food, which they pull below the surface. Here, part of the 

 material is eaten, while vast quantities of it pass into vegetable 

 mould that helps to make other plants grow. [Editorial note: 

 All vegetable remains not immediately consumed, are eventually 

 eaten and pass through the alimentary canals of worms in their 

 final transformation into humus or soluble plant food.] 



In addition to the vegetable matter which the worms eat, great 

 quantities of soil also pass through this vast army. From this 

 soil they assimilate what is useful to them, leaving the remainder 

 each night upon the surface in the lobed and familar castings 

 which everyone has seen. Stop for a minute to consider the 

 countless individual worms which inhibit every acre of ground. 

 Think then of the weight and depth of a single year's castings 

 that are left upon the surface and you will begin to realize that 

 the worms are actually responsible for the ploughing and turning 

 over of the earth as the years go by. 



Continuing our journey through the earthworm, all the in- 

 gested material vegetable matter, animal matter, living and dead 

 bacteria, mineral earth, small stones, etc. passes into the crop 

 and thence into the gizzard as a semi-liquid, plastic mass, carry- 

 ing its own grindstones. In the gizzard everything is subjected 

 to the grinding, disintegrating and mixing action of this efficient 

 organ, as the abundant digestive juices are poured in to exert 

 their chemical and solvent action. No form of organic material 

 escapes, for the digestive secretions of the earthworm are similar 

 to those of the higher animals, including the human family. Car- 

 bohydrates, fats, proteins, cellulose all are grist for the mill of 

 the earthworm; for anything that cannot be digested is at least 

 so finely comminuted that no structural form remains. 



Special mention should be made of the highly remarkable 

 calciferous glands which are located in the walls of the esophagus 

 of the earthworm. Nothing like them is known in any other ani- 

 mal. These calcium-secreting glands pour out abundant quanti- 



