288 Dr Davy's Jgricultural Discourse. 



Conclusions. 



1. A latent power of hybridity exists in many animals in 

 the wild state, in which state, also, hybrids are sometimes 

 produced. 



2. Hybridity occurs not only among different species, but 

 among different genera ; and the cross-breeds have been pro- 

 lific in both cases. 



3. Domestication does not cause this faculty, but merely 

 evolves it. 



4. The capacity for fertile hybridity, cceteribus paribus, 

 exists in animals in proportion to their aptitude for domesti- 

 city and cultivation. 



5. Since various different species of animals are capable of 

 producing together a prolific hybrid offspring, hybridity 

 ceases to be a test of specific affiliation. 



6. Consequently, the mere fact that the several races of 

 mankind produce with each other a more or less fertile pro- 

 geny, constitutes, in itself, no proof of the unity of the human 

 species. 



A Discourse. By John Davy, M.D., F.R.S., Inspector-Ge- 

 neral of Army Hospitals, Honorary Member of the Ge- 

 neral Agricultural Society of Barbadoes. Read at their 

 Third Half- Yearly Meeting in 1847. 



Gentlemen, — In the discourse I am about to have the 

 honour to address to you, it is my intention to bring under 

 your notice the subject of manures. To you, as practical 

 agriculturists, I need not insist on, or endeavour to point 



the other hand, some undergo very remarkable changes in a state of nature, as 

 some species of squirrel, fox, wolf, &c., while other species of the very same 

 genera undergo no change whatever. Hence the fallacy of drawing inferential 

 conclusions from those that do change, in order to explain the phenomena of 

 diversity among men. 



The diversities of animals are in some cases owing to exterior causes alone ; 

 in other instances they arise solely from amalgamation of species ; while in a 

 third class we can trace the operation of both these agents. 



