On Species. 309 



these units capable of blending witli one another indefinitely, 

 thej would no longer be units, and species could not be recog- 

 nized. The system of life would be a maze of complexities ; 

 and whatever its grandeur to a being that could comprehend the 

 infinite, it would be unintelligible chaos to man. The Yery beau- 

 ties that might charm the soul would tend to engender hopeless 

 despair in the thoughtful mind, instead of supplying his aspira- 

 tions with eternal and ever-expanding truth. Jt would be to 

 man the temple of nature fused over its whole surface and 

 through its structure, without a line the mind could measure or 

 comprehend. 



Looking to facts in nature, we see accordingly every where, 

 that the purity of species has been guarded with great precision. 

 It strikes us naturally with wonder, that even in senseless plants, 

 Without the emotional repugnance of instinct, and with repro- 

 diictive organs that are all outside, the free winds being often 

 the means of transmission, there should be ris'id law sustained 

 against intermixture. The supposed cases of perpetuated fertile 

 nybridity are so exceedingly few as almost to condemn them- 

 selves, as no true examples of an abnormity so abhorrent to the 

 system. They violate a principle so essential to the integrity of 

 the plant-kingdom, and so opposed to nature's whole plan, that 

 we rightly demand long and careful study before admitting the 

 exceptions. 



A few words will explain what is meant by perpetuated fertile 

 hybriditj^ The following, are the supposable grades of results 

 from intermixture between two species: — 



1- No issue whatever — the usual case in nature. 



2, Mules (naming thus the issue) that are wholly infertile 

 "whether among themselves or in case of connection with the 

 piire or original stock. 



8. Mules that are wholly infertile among themselves, but may 

 have issue for a generation or two by connection with one of the 



original stock. 



4. Mules that are wholly- infertile among themselves, but may 

 We issue through indefinite generations by connection for each 

 with an individual of the original stock. 



5. Mules tbat are fertile among themselves tbrougb one or 



two generations. 



6. Mules that arc fertile among themselves through many gen-^ 

 €^rations. 



^ 7. Males that are fertile among themselves through an indefi* 

 ^ite number of generations. 



The cases 1 to 5 are known to be established facts in nature ; 

 ''^nd each bears its testimony to the grand law of purity and per- 

 manence. The examples under the heads 2 to 5 become sever- 

 ely less and less numerous, and art must generally use an un- 

 liatural play of forces or arrangements to bring them about. 



