42 I THE HOME, FARM AND BUSINESS CYCLOPEDIA. 



other, but cannot be distinguished by any permanent or marked differ- 

 ence. Although there may be some variation in size and other minor 

 points, still we at once say they are stalks of wheat. Every grain of 

 wheat, when sown, produces a stalk of wheat ; these stalks yield grains, 

 which produce individuals like their parents. The shoots or buds given 

 off from the base of wheat by tillering also produce stalks of wheat. On 

 such universal and inevitable conceptions as these, our ideas of Species 

 are founded. 



A Species may be defined as an assemblage of individuals presenting 

 certain constant characters in common, and derived from one original 

 stock. For each species we believe that there has been a parent stock, 

 which has given origin to a succession of similar individuals. They may 

 differ slightly in size, or in colour, and other unimportant respects, but 

 they resemble each other more closely than they resemble any other plant, 

 and their seeds produce similar individuals. Observation and common 

 daily experience demonstrate, in the actual circumstances in which we 

 exist, the permanence of the types which constitute the species of living 

 bodies. There is no evidence whatever of a transmutation of species. 

 The erroneous statement regarding the conversion of oats into rye or 

 wheat into chess have proceeded from imperfect observations. The indi- 

 viduals, however, of a species may present certain differences in regard to 

 size, colour, etc., these differences depending on soil, and on varying con- 

 ditions of heat, light, and moisture. Such differences are not incompat- 

 ible with the idea of a common origin, and, moreover, there is always a 

 tendency to return to the original type. What are called Varieties there- 

 fore, are variations in specie^ which are not in general of a permanent 

 character, and cannot be kept up in ordinary circumstances by seed. By 

 cultivation, however, such varieties are sometimes perpetuated. This is 

 usually accomplished by means of cuttings or grafts, and in certain instan- 

 ces even by seed. Thus the varieties of the cereal grains and of culinary 

 vegetables have been propagated so as to constitute permanent Races. 



Plants under cultivation are liable to sport, as it is called, and the pecu- 

 liarities and variations thus produced are sometimes kept up. All the 

 varieties of cabbage, cauliflower, broccoli, savoys, and curled greens, are 

 derived from one stock Brassica oleracea. This plant grows wild on 

 the sea-shore, and when cultivated it undergoes remarkable changes. 

 Thus it forms a heart, as in ordinary cabbage ; its flower-stalks become 

 thickened and shortened, as in cauliflower and broccoli ; or cellular tissue 

 is largely developed between the vessels of the leaves, so as to give rise 

 to the crisp and curly appearance of the greens. This tendency in the 



