7Z PLAIN FACTS FOR OLD AND YOUNG 



REPRODUCTION 



Nutrition and reproduction are tlie two great func- 

 xions of life, being common, not only to all animals, 

 but to both animals and plants, to all classes of living 

 creatures. The object of the first is the development 

 and maintenance of individual existence; the second 

 has for its end the production of new individuals, or 

 the preservation of the race. Nutrition is a purely 

 selfish process; reproduction is purely unselfish in its 

 object, though the human species, unlike humbler 

 creatures, which while less intelligent, are far more 

 true to nature, too often pervert its functions to the 

 most grossly selfish ends. 



Reproduction Common to All Living Things. — 

 As before remarked, reproduction is a function com- 

 mon to all animals and to all plants. Every organized 

 being has the power to reproduce itself, or to produce, 

 or aid in producing, other individuals like itself. It is 

 by means of this function that plants and animals in- 

 crease or multiply. 



AVhen we consider the great diversity of characters 

 illustrated in animal and vegetable life, and the infinite 

 variety of conditions and circumstances under which 

 organized creatures exist, it is not surprising that 

 modes of reproduction should also present great di- 

 versity, both in general character and in detail. We 

 shall find it interesting and instructive to consider some 

 of the many different modes of reproduction, or gener- 

 ation, observed in different classes of living beings, 

 previous to entering upon the specific study of repro- 

 duction in man. Before doing this, however, let us 

 give brief attention to a theoretical form of genera- 

 tion, which cannot be called reproduction, known as — 



