CHAPTER V. 



AS TO SPECIFIC STABILITY. 



What is meant by the phrase "specific stability;" such stability to be 

 expected a priori, or else considerable changes at once. Increasing 

 difficulty of intensifying race characters ; alleged causes of this pheno- 

 menon ; probably an internal cause co-operates. A certain definiteness 

 in variations. Mr. Darwin admits the principle of specific stability in 

 certain cases of unequal variability. The goose. The peacock. The 

 guinea-fowl. Exceptional causes of variation under domestication. 

 Alleged tendency to reversion. Instances. Sterility of hybrids. 

 Prepotency of pollen of same species, but of different race. Mortality 

 in young gallinaceous hybrids. A bar to intermixture exists some- 

 where. Guinea-pigs. Summary and conclusion. 



As was observed in the preceding chapters, arguments 

 may yet be advanced in favour of the opinion that species 

 are stable (at least in the intervals of their comparatively 

 sudden successive manifestations) ; that the organic world 

 may be symbolized according to Mr. Gallon's before -men- 

 tioned conception, by many facetted spheroids, each of which 

 can repose upon any one facet, but, when too much disturbed, 

 rolls over till it finds repose in stable equilibrium upon 

 another and distinct facet. It is here contended then that 

 something may be urged in favour of the existence of 

 such facets of such intermitting conditions of stable 

 equilibrium. 



A view as to the stability of species, in the intervals of 

 change, has been well expressed in an able article, before 



