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General Characters of Animals. 5 



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There are three stages in the contest between waste 

 and repair which is characteristic of life. In the first, 

 repair is in excess of waste, and individual growth 

 proceeds until a definite limit, constant within certain 

 bounds for each specres, is reached. When this is 

 attained, excess of nutrition still continues but tends 

 to become separate and independent ; by such dis- 

 continuous modes of growth, the third set of functions, 

 or Reproduction, is accomplished. Of this there are 

 ree chief forms : (A) either the whole body of the 

 arent may split into two or more, each becoming a 

 perfect animal like its parent ; this process is named 

 fission (fig. i ). (B) In the second mode of reproduction 

 a small portion of the body of the parent animal 

 enlarges and becomes detached as a bud, which de- 

 velops directly into an organism like its ancestor ; this 

 is called gemmation (fig. 2). (c) In the FlG - 2 - 

 third mode small particles called eggs arise 

 from the tissues of the parent, and, on being ' 

 fertilised by union with organic particles from ' 

 another organism, are capable of developing 

 into newindividuals ; this is called ovulation. 



The second stage of existence having 

 for a time continued, the organism reaches 

 a third stage, in which waste exceeds repair, 

 and as, by degrees, the assimilated material Gemmation In 



'.'.-. , the common 



becomes insufficient to keep up the pro-//Wr^r/^>. 

 cesses of life this stage terminates in death. 



Summary. Animals consist for the most part of 

 protoplasm, are constantly undergoing waste, and 

 being built up by the assimilation of food. They 

 differ from plants in being usually capable of loco- 



