Human Physiology. 245 



trees by moulding a ball of earth upon a twig, keeping it moist, 

 and making a section in the bark below it. When roots have 

 penetrated the earth they cut it off and plant it. Each bud of 

 a tree has its distinct life, and in most cases can be transferred 

 to another tree of an allied species and made to grow, produc- 

 ing, however, its own peculiar flowers and fruit. Each bud is 

 a germ ; the seed germs are similar, but differ at least in this, 

 that they sometimes produce, as in potatoes and apples, new 

 varieties. A bud or graft gives us the same fruit as its parent 

 tree. A tree which grows from an apple seed may produce 

 very different fruit. For this reason, when fruit trees are grown 

 from seeds, gardeners bud or graft them; that is, transfer to 

 them buds or twigs from trees producing a favourite variety, 

 and let the transferred buds grow to form the future trees. 



Low forms of vegetation, as the various kinds of fungi and 

 ferns are produced from spores, which are germs or rudimen- 

 tal buds rather than seeds. They are very small, produced by 

 myriads, as in the puff ball, and are so light as to be blown 

 about by the winds, and almost fill the atmosphere. Where- 

 ever air can penetrate, it carries with it the germs of vegetation 

 as well as those of the lower forms of animal life. 



But it is in our lovely and odorous flowers that we have the 

 highest types of the generation of vegetable life; and the 

 favourite science of Botany largely consists of the study of the 

 organs and processes of vegetable reproduction, or what the 

 Elder Darwin in his curious poem calls the Loves of the Plants, 

 which present us with the most delightful analogies to the 

 higher processes of reproduction in animals and our own 

 species. Botany is therefore a charming introduction to all 

 other branches of natural history, and especially to that branch 

 of human physiology which we are now considering. 



