572 



GARDENERS' CHRONICLE 



Composition of Living Things 



WILLARD N. CLUTE 



IF a pile of ashes should suddenly come to life and 

 amble down the street, the occurrence would be 

 regarded as one of the greatest of miracles, and 

 yet th?s is not far from what has happened in the case 

 of living matter. All the materials of which this sub- 

 stance is composed may be found in the ordinary ash- 

 pile. A certain amount of water and carbon dioxide 

 and minute portions of iron, sulphur, phosphorus, cal- 

 cium, magnesium, nitrogen and potassium are all that 

 are required. These are among the commonest sub- 

 stances in the whole world and, by themselves, are 

 inert, lifeless, and in no essential way different from 

 the eighty other substances called chemical elements 

 of which' the earth itself is composed, but joined in 

 the right way they take on life ; they move, feel, think, 

 and are thus able to control all the others. 



The elements thus combined are the only ones that 

 are known to combine to form living substance or 

 protoplasm, but thus combined, they are endowed with 

 new and wonderful powers. They are now able to 

 promote the further combination of the elements, ab- 

 sorbing these lifeless things from their surroundings 

 and building them up, sometimes into living matter 

 and at others into numberless other forms which are 

 clearly chemical compounds but which are not gifted 

 with life and are unable to alter their own conditions. 

 Moreover, when any of the elements in these com- 

 pounds are no longer useful they may be excluded 

 from the comliinations and either thrown out or com- 

 bined anew. 



Most astonishing of all the qualities characteristic 

 of protoplasm, is its immortality. The elements of 

 which it is composed are themselves immortal in the 

 sense that they have existed since the beginning and 

 are no more or no less in amount than at first, but 

 protoplasm has a new immortality in that the processes 

 within it, which for want of a better word we call life, 

 may go on forever. Many of the combinations built 

 up are not and never were alive, and even some forms 

 of protoplasm lack immortality ; nevertheless, all the 

 protoplasm now in the world has come from pre-ex- 

 isting protoplasm and does not arise dc nozw by new 

 combinations of the elements of which it is composed. 

 All life from life has ever been the rule. Though the 

 chemist can name the elements in protoplasm and give 

 the exact proportions of each, the wisest of his pro- 

 fession cannot make even the smallest globule of it. 



Since there is but one living substance it follows 

 that all living things consist of protoi)lasm and yet 

 most living things are not immortal. Nearly all have 

 a definite life-cycle which begins with youth and runs 

 on through maturity and old age to death. Before 

 the final scene, however, the organism hands along to 

 a new generation bits of its own protoplasm and in 

 this sense is immortal for it lives in its descendants. 

 In those forms which extend their race by simply split- 

 ting in half and continue this process in endless repe- 

 tition, the forms are not only immortal but comprise 

 within themselves a part of all their ancestors. The 

 function of reproduction may occur but once in the 

 life-cycle, in the case of complex forms, it may occur 

 many times though seldom occurring until the organ- 

 ism has reached maturity. In those forms whose race 

 is run. that is, when the acti\-ities nf combination and 



re-combination have ceased, the organism gradually 

 breaks down into its original elements and may then 

 be re-absorbed and used in another body. 



A remarkable feature of protoplasm is its wide dis- 

 tribution and the myriad of forms it assumes in ad- 

 justing itself to its surroundings. From pole to pole, 

 from mountain heights to ocean depths, there are few 

 places into which it has not penetrated. It burrows 

 in the earth, it creeps on its surface, it invades the 

 welters, it glides through the air, it even turns upon 

 its own and lives within or upon many forms. 



All the activities of protoplasm are connected with, 

 and dependent upon, the storage or release of force, 

 or energy. Some forms secure their energy by pro- 

 moting the union of oxygen with other elements, but 

 the majority snatch it from the sunlight, turning some 

 of the ravs into electric energy with which they build 

 up combinations of carbon, hydrogen and oxj-gen into 

 stable forms, that may be used when needed. There 

 are, however, a large number of organisms which can- 

 not obtaiti their energy direct from Nature but must 

 take it as best they can from those who originally ob- 

 tained it. These forms we call animals. Those which 

 secure their energy direct we call plants. In the course 

 of ages, manv plants have become parasites like the 

 animals and, like them, dependent upon others for 

 energy, but all ordinarily green plants are independ- 

 ent. In the matter of liberating energy, however, both 

 animals and plants are alike. By uniting oxygen with 

 the carbon in the combinations built up, they break 

 them down and release their energy. 



It is easy to perceive that plants and animals are 

 very much alike. Both originate from pre-existing 

 individuals, both absorb new materials from their sur- 

 roundings, both grow or increase in size, both respire 

 or breathe, both excrete, secrete and reproduce. Both 

 have a life cycle of youth, maturity, old age and death, 

 and if the term of life in plants is often less definite 

 than in animals, the end is none the less inevitable. 

 The animals are more highly developed than the 

 plants and have more complex organs for carrying on 

 their activities but no essentially new activities are 

 developed. Plants, for instance, respire exactly as 

 animals do, but they lack the lungs, .gills, spiracles and 

 other organs by means of which animals respire. 



A distinction often made between animals and 

 plants is that animals move about and plants do not. 

 This distinction is more seeming than real. There 

 are numerous animals that are fixed in one place when 

 mature, oysters and barnacles for example, while the 

 young of plants, while still in the -seed, move about 

 as freely as animals but not by their own efforts. One 

 noticeable difference between animals and plants is 

 that animal tissues have a preponderance of nitrogen 

 while the tissues of plants are largely carbonaceous. 

 Animals have a more definite shape and size than 

 plants and they have nerves and a brain or nerve cen- 

 ters while plants lack these structures. Animals feel 

 and know, but while it is very evident that plants feel. 

 as a whole they are not con.scious of it. The most 

 fundamental difference however is found in the fact 

 that ])lants are food makers, building up simple sub- 

 stances into more complex molecules, while animals 

 are food destroyers, tearing down complex substances 

 into simpler forms. 



