194 LIFE ON THE EARTH. 



experience appears to shew on the contrary, that, in 

 the actual state of the globe, varieties are restrained 

 within rather narrow limits, and as far back as we 

 ascend into antiquity we see that these limits were 

 the same then as now. 



' We are therefore obliged to admit certain forms, 

 which have been perpetuated since the origin of 

 things without exceeding these limits; and all the 

 beings which appertain to one of these forms con- 

 stitute what is called a species. Varieties are the 

 accidental subdivisions of the species. 



' Generation being the only means of knowing the 

 limits to which varieties can extend, a species may 

 be defined, as comprising the individuals, descended 

 one from another or from common parents, and those 

 which resemble them as much as they resemble each 

 other. 



' These forms do not produce or change them- 

 selves ; life supposes their existence ; it can only be 

 kindled in organizations ready prepared for it; and 

 the most profound meditations, as well as the most 

 delicate observations, reach no further than to the 

 mystery of the pre-existence of germs.' 



PRIMITIVE TYPES. 



The illustrious author of the Systema Naturce 

 permitted his accurate and richly stored mind some- 



