6 



life in the world (whenever that may have been) there has been 

 one continuously connected stream of life ; no universal destruction, 

 no gap or blank ; with the progress of time living forms, both 

 animal and vegetable have multiplied without cessation, both in 

 number and variety. How, again, did the rariety, the new forms, 

 appear ? Were they each individually fashioned, perfect in form 

 and kind, or were several forms developed out of one ? The 

 advocates of development adhere to the latter view : e.//. that all 

 kinds of elephant have descended from one origmal form, not 

 exactly like any of them ; so with all forms of rhinoceros, hippo- 

 potamus, tapir, &c. — that all these various forms may probably 

 have had one common ancestor ; that all butterflies have descended 

 from an ancestor probably common to them and tu moths, — that 

 indeed all insects have had a common origin ; and so with flowers. 

 You vv'ill ask upon what grounds such a view has been adopted. 

 I will sum them up briefly. 



1. — No two animals or plants of the same kind are exactly alike. 

 There is an innate and unexplained tendency in each to vary from 

 its parent in some particulars more or less sliglit, in spite of its 

 general resemblance. This requires no proof whatever ; you never 

 find two leaves on the same tree, one the exact duplicate of the 

 other. 



2. — Such variations can be, and very often are, transmitted to 

 offspring — the latter tends to inherit the peculiarities of its parent. 

 These peculiarities may be either an advantage or a disadvantage, 

 it depends on circumstances around. 



3. — More animals and plants are produced than could possibly 

 find room on the earth if they lived what one might call their 

 natural term of life. Therefore many disappear in a more or less 

 abrupt manner. But which of them ? 



4. — Surely those whose peculiarities were a disadvantage to them. 

 If a variation in certain individuals better fitted them either to 

 obtain food, or to escape from enemies, these individuals would be 

 preserved while the less favoured ones perished. Those that are 

 best adapted to surrounding physical circumstances — they will be 

 the survivors. The carnivore that can catch the most food when 

 it is scarce ; the deer tliat by its longer legs or stronger muscles can 

 best escape the beast of prey ; the sheep that has the thickest 

 fleece when climate changes for the worse, &c. This has been 

 happily styled " the survival of the fittest." 



Just as man selects those animals and plants best suited to his 

 wants on account of some accidental variation, and breeds from 

 them, thereby artificially producing new varieties, if not species, so 

 there is a "natural selection " going on around us; some hold 

 merely through the working of a blind law, others, through a con- 



