 | Sir Charles Lyell - 1832 - 368 sider
...least possible excess beyond the defined limits being fatal to the existence of the individual. Sthly. The intermixture of distinct species is guarded against...and not to the intermixture of hybrid with hybrid. 6thly. From the above considerations, it appears that species have a real existence in nature, and... | |
 | Benjamin Godwin - 1834 - 314 sider
...possible excess beyond the defined limits being fatal to the existence of the individual. " oth ly, The intermixture of distinct species is guarded against...and not to the intermixture of hybrid with hybrid. "6thly, From the above considerations, it appears that species have a real existence in nature, and... | |
 | Benjamin Godwin - 1835 - 384 sider
...kind of change can produce, may usually be effected in a brief period of time, after which no further deviation can be obtained by continuing to alter the...mules with individuals of pure species, and not to the intermixure of hybrid with hybrid. " Gthly. From the above considerations, it appears that species... | |
 | sir Charles Lyell (bart.) - 1840 - 504 sider
...effected in a brief period of time, after which no farther deviation can be obtained by conr tinuing to alter the circumstances, though ever so gradually...and not to the intermixture of hybrid with hybrid. 6thly. From the above considerations, it appears that species have a real existence in nature ; and... | |
 | 1850 - 608 sider
...least excess beyond the defined limits being fatal to the existence of the individual. 1 ."•!•!. The intermixture of distinct species is guarded against...relate to the crossing of mules with individuals of the pure species, and not to the intermixture of hybrid with hybrid. ' 6th. From these considerations... | |
 | 1850 - 600 sider
...and the least excess beyond the defined limits being fatal to the existence of the individual. " 5th. The intermixture of distinct species is guarded against...relate to the crossing of mules with individuals of the pure species, and not to the intermixture of hybrid with hybrid. " 6th. From these considerations... | |
 | John Holmes Agnew, Walter Hilliard Bidwell - 1850 - 604 sider
...and the least excess beyond the defined limits being fatal to the existence of the individual. " 5th. The intermixture of distinct species is guarded against...sterility of the mule offspring. It does not appear tiiat true hybrid races have ever been perpetmted for several generations, even by the assistance of... | |
 | 1857 - 520 sider
...constant laws, and the capability of so varying forms part of the permanent specific character. " 3rdly. Some acquired peculiarities of form, structure, and...and not to the intermixture of hybrid with hybrid. "6thly. From the above considerations, it appears that species have a real existence in nature ; and... | |
 | Thomas Ragg - 1858 - 456 sider
...can produce, may usually be effected in a brief period of time, after which no deviation can be made by continuing to alter the circumstances, though ever...of man ; for the cases usually cited relate to the crossings of mules with individuals of pure species, and not to the intermixture of hybrid with hybrid.... | |
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The intermixture of distinct species is guarded against by the aversion of the individuals composing them to sexual union, or by the sterility of the mule offspring. It does not appear that true hybrid races have ever been perpetuated for several generations,... 
