90 BIOLOGY: GENERAL AND MEDICAL 



complex molecule, and then a still more complex arrange- 

 ment: 



nC 6 H 12 O 6 -nH 2 O = (C 6 H 10 O 5 )n (starch and cellulose) 

 by which starch and cellulose are made. 



At this point we reach products capable of subserving 

 many different purposes. Doubtless further more com- 

 plex syntheses are immediately effected, though the 

 cellulose being a structural element of importance to 

 the plants is commonly deposited in permanent form 

 where needed, and the starch is temporarily deposited 

 in scattered granules or in dense aggregations, as in 

 potatoes, peas, beans, fruits, etc., until needed for further 

 transformations. 



At this stage we reach also the point at which the utili- 

 zation of the plant products by animals becomes possible, 

 starch forming one of the most valuable foods of the 

 higher animals. 



Beyond this point the progress of the synthetic process 

 can no longer be followed, because the complexity of the 

 molecular compounds becomes too great. 



REPRODUCTION. 



As living beings are subject to such wear and tear as 

 results from their activities and to accidents of various 

 kinds, the persistence of life is dependent upon the 

 ability of living substance to reproduce its own kind, 

 Reproduction is, therefore, a fundamental manifestation 

 of life. 



The new individual, no matter how produced, is 

 endowed with potentialities and possibilities the sum of 

 which constitute youth and, therefore, constitutes a new 

 generation qualified to repeat not only the structure, but 

 also the functions of its parent. 



As will be shown in a future chapter, the particular 

 form of reproduction varies with the simplicity or com- 

 plexity of structure, yet all forms of reproduction are 

 ultimately referable to simple phenomena, such as are 



