| Comparison with 1872 | 
  | 
it seems to me 
impossible to resist the evidence of the existence of a certain amount of sterility in the few following cases, which I will briefly abstract.  The evidence is at least as good as that from which we believe in the sterility of a multitude of species.  The evidence is, also, derived from hostile witnesses, who in all other cases consider fertility and sterility as safe criterions of specific distinction.  Gärtner kept during several years a dwarf kind of maize with yellow seeds, and a tall variety with red seeds, 
growing near each other in his garden; and although these plants have separated sexes, they never naturally crossed.  He then fertilised thirteen flowers of the one 
 kind with | kind with 1872 |  | with the 1859 1860 1861 1866 1869 |  
  
pollen of the other; but only a single head produced any seed, and this one head produced only five grains.  Manipulation in this case 
could not have been injurious, as the plants have separated sexes.  No one, I believe, has suspected that these varieties of maize are distinct species; and it is important to notice that the hybrid plants thus raised were themselves 
perfectly 
fertile; so that even Gärtner did not venture to consider the two varieties as specifically distinct.  | 
 | 
|  Girou de Buzareingues crossed three varieties of gourd, which like the maize has separated sexes, and he asserts that their mutual fertilisation is by so much the less easy as their differences are greater.  How far these experiments may be trusted, I know not; but the forms experimentised 
on, 
are ranked by Sagaret, 
who mainly founds his classification by the test of infertility, as varieties. 
 | 
 | 
 The following case is far more remarkable, and seems at first 
 ..| ..... 1872 |  | quite 1859 1860 1861 1866 1869 |  
  
incredible; but it is the result of an astonishing number of experiments made during many years on nine species of Verbascum, by so good an observer and so hostile a witness, 
as Gärtner: 
 namely | namely 1872 |  | namely, 1859 1860 1861 1866 1869 |  
  
that yellow 
 | 
 
  
  
it 
 is | is 1861 1866 1869 1872 |  
| seems to me 1859 1860 |  
  
impossible to resist the evidence of the existence of a certain amount of sterility in the few following cases, which I will briefly abstract.  The evidence is at least as good as that from which we believe in the sterility of a multitude of species.  The evidence is, also, derived from hostile witnesses, who in all other cases consider fertility and sterility as safe criterions of specific distinction.  Gärtner kept during several years a dwarf kind of maize with yellow seeds, and a tall variety with red 
 seeds | seeds 1869 1872 |  | seeds, 1859 1860 1861 1866 |  
  
growing near each other in his garden; and although these plants have separated sexes, they never naturally crossed.  He then fertilised thirteen flowers of the one 
 with the | with the 1859 1860 1861 1866 1869 |  | kind with 1872 |  
  
pollen of the other; but only a single head produced any seed, and this one head produced only five grains.  Manipulation in this 
 case | case 1859 1860 1866 1869 1872 |  | ease 1861 |  
  
could not have been injurious, as the plants have separated sexes.  No one, I believe, has suspected that these varieties of maize are distinct species; and it is important to notice that the hybrid plants thus raised were themselves 
perfectly 
fertile; so that even Gärtner did not venture to consider the two varieties as specifically distinct.  | 
 | 
 Girou de Buzareingues crossed three varieties of gourd, which like the maize has separated sexes, and he asserts that their mutual fertilisation is by so much the less easy as their differences are greater.  How far these experiments may be trusted, I know not; but the forms 
 experimented | experimented 1861 1866 1869 1872 |  | experimentised 1859 1860 |  
  
 on | on 1861 1866 1869 1872 |  | on, 1859 1860 |  
  
are ranked by 
 Sageret, | Sageret, 1866 1869 1872 |  | Sagaret, 1859 1860 1861 |  
  
who mainly founds his classification by the test of infertility, as 
 varieties, and Naudin has come to the same conclusion. | varieties, and Naudin has come to the same conclusion. 1866 1869 1872 |  
| varieties. 1859 1860 1861 |  
  
 | 
 | 
 The following case is far more remarkable, and seems at first 
 quite | quite 1859 1860 1861 1866 1869 |  quite 1872 |  
  
incredible; but it is the result of an astonishing number of experiments made during many years on nine species of Verbascum, by so good an observer and so hostile a 
 witness | witness 1861 1866 1869 1872 |  | witness, 1859 1860 |  
  
as Gärtner: 
 namely, | namely, 1859 1860 1861 1866 1869 |  | namely 1872 |  
  
that 
 the yellow | the yellow 1869 1872 |  | yellow 1859 1860 1861 1866 |  
  
 |