The Earth Worm (1937)

among man's valued servants are the earthworms by tireless borrowing and feeding they loosen aate and enrich the soil the anterior end of the earthworm with which it borrows many tunnels to a depth of 5 or 6 ft is tapering the posterior end is blunt if an earthworm is viewed under a magnifying glass hundreds of pairs of bristles which assist Locomotion can be seen called CT these may be felt when a live worm is placed upon the hand they are in groups of four pairs each two on the lateral sides of the body and two on the under or ventral side the earthworm's body is made up of sections numbering from 120 to more than 200 depending on its age and species each section except the first and last is equipped with four pairs of CT the worm gains Locomotion by The Joint action of its bristles and sections the skin of the body is flexible and permits the worm to expand or contract the sections by muscular action to go forward or backward the animal clings to the ground with part of its sections raises the others and draws them forward the bristles on the elevated sections are folded back to be clear of the ground but are again extended when these sections are lowered to hold them firmly to the Earth while other sections are being moved by repeated movements of this nature the worm is able to crawl easily and rapidly ctm sections working in Perfect Harmony place a worm on a piece of smooth glass where the bristles cannot grip while it will make some progress its movements are slow and uncertain the earthworm has a well- defined mouth with protruding round lips with which it picks up particles of food the farx is a muscular chamber which forms a suction cup to Aid the mouth in drawing in food the food passes into the gullet where it mixes with a carbonate of lime solution which when it has left the worm counteracts soil acidity in the crop a crude stomach the food is mixed with digestive juices it then enters the gizard a muscular organ containing Stones which grind the coarse earthy food into a pulverized Mass upon reaching the intestine the nutritive values pass into the blood the nondigestible portion expelled as casting the castings of finely ground Earth particles improve soil fertility by carrying into their borrows much vegetable matter which rots into mold and then restoring it to the surface earthworms build up the top soil as much as 1/1 of an inch per year overcoming in part the effects of erosion it is estimated that an acre of fertile ground contains as many as 45,000 earthworms a colorless liquid in the body cavity surrounds the vital organs it protects the worm from the Earth's coldness keeps it clean and shiny and acts as a lubricant to Aid the passage of the body in the burrow near the front of the body are the so-called Hearts they expand and contract forcing a steady flow of blood along the main bloodstream which passes through them the red blood which circulates chiefly in the walls of the digestive organs may be easily seen by an examination of the upper part of an earthworm's body the blood flows throughout the entire length of the body with many tiny branches entering the vital organs as it passes from section to section it is purified by air which enters the body through tiny pores between the sections and is absorbed into the bloodstream the oxygen in the air displaces the carbon dioxide in the blood which escapes through similar pores the worm therefore is seen to breathe through the pores of its skin other impurities are removed from the body through the nefa which function as kidneys giving the worm an elaborate and effective system for eliminating the large amount of indigestible matter of which its earthy food is composed each kidney consists of three sections a funnel like orifice opens into the body cavity a tube p passes from it through the walls of each adjoining section into a muscular sack which opens into exterior pores the waists are forced through the pores by the muscular contraction of the sac because the worm chooses the easiest way to draw leaves into its burrow it is credited with some intelligence the first gangion which corresponds to the brain is a nerve cluster located above the mouth and the center of the animal's extensive nervous system after branching around the mouth this gangling is connected by a ring of nerves to a chain of ganglia in the lower part of the body though it has neither sight or hearing the worm's highly developed nervous system makes it very sensitive to touch and soil vibrations it is also sensitive to light rarely leaving its burrow in daytime except after a heavy rain or unless disturbed by vibrations the earthworm carries within its body both male and female organs two minute sexs called spermaries contain the male generative fluid funnel-shaped tubes connect the spermaries to exterior pores on the underside in adjoining sections are the female egg sacks or ovaries which likewise open into exterior pores to reproduce however the worm must come in contact with another worm when this happens the sperm is discharged through the spermatic ducts to enter the body of the other worm whose sperm in return enters the two receiving Chambers lying under the first worm's spermaries when the eggs are ripe a section of rings encircling the worm's body called the clitellum swells loosens and slowly Works forward as it passes the exterior generative vents the eggs are released and fall into the clitellum when all the eggs have been deposited the stored up sperm cells are discharged from their Chambers each cell attaching itself to an egg for the sake of clearness the picture shows the clitellum stationary as the eggs and sperm are deposited though actually it is slowly moving forward and is finally cast off by the worm crawling out of it then it closes imprisoning the eggs in a conun until they have hatched a new clitellum is formed many times a year following each reproductive process to take the place of the one which is shed the newly born worms are very tiny and many of them die but enough enough live and grow to adult animals to carry on without interruption the great work which Nature has laid out for the lowly earthworm family