| Comparison with 1872 | 
  | 
 
Hybrids
 | 
Hybrids
 1866 1869 1872 |  | 
Hybrids
 1859 1860 1861 |  
  
 
and
 | 
and
 1866 1869 1872 |  | 
and
 1859 1860 1861 |  
  
 
Mongrels
 | 
Mongrels
 1866 1869 1872 |  | 
Mongrels
 1859 1860 1861 |  
  
 
compared
,
 | 
compared
,
 1872 |  
| 
compared,
 1859 1860 |  
| 
compared
,
 1861 |  
| 
compared,
 1866 1869 |  
  
 
independently
 | 
independently
 1866 1869 1872 |  | 
independently
 1859 1860 1861 |  
  
 
of
 | 
of
 1866 1869 1872 |  | 
of
 1859 1860 1861 |  
  
 
their
 | 
their
 1866 1869 1872 |  | 
their
 1859 1860 1861 |  
  
 
fertility
.  | 
fertility
.  1872 |  | 
fertility
.—
 1859 1860 1861 |  | 
fertility
.
 1866 |  | 
fertility
.  1869 |  
  
 | 
 Independently of the question of fertility, the offspring of species 
 ..| ..... 1872 |  | when crossed 1859 1860 1861 1866 1869 |  
  
and of varieties when crossed may be compared in several other respects.  Gärtner, whose strong wish was 
to draw a marked 
line of distinction 
between species and varieties, could find very few 
and, as it seems to me, quite unimportant differences between the so-called hybrid offspring of species, and the so-called mongrel offspring of varieties.  And, on the other hand, they agree most closely in 
 ..| ..... 1866 1869 1872 |  | very 1859 1860 1861 |  
  
many important respects.  | 
 | 
 I shall here discuss this subject with extreme brevity.  The most important distinction is, that in the first generation mongrels are more variable than hybrids; but Gärtner admits that hybrids from species which have long been cultivated are often variable in the first generation; and I have myself seen striking instances of this fact.  Gärtner further admits that hybrids between very closely allied species are more variable than those from very distinct species; and this shows that the difference in the degree of variability graduates away.  When mongrels and the more fertile hybrids are propagated for several 
 generations, | generations, 1869 1872 |  | generations 1859 1860 1861 1866 |  
  
an extreme amount of variability in 
 the | the 1869 1872 |  | their 1859 1860 1861 1866 |  
  
offspring 
 in both cases is | in both cases is 1869 1872 |  
| is 1859 1860 1861 1866 |  
  
notori- ous; 
but some few 
 instances of both | instances of both 1869 1872 |  
| cases both of 1859 1860 1861 1866 |  
  
hybrids and mongrels long retaining 
 a uniform | a uniform 1869 1872 |  | uniformity of 1859 1860 1861 1866 |  
  
character could be given.  The variability, however, in the successive generations of mongrels is, perhaps, greater than in hybrids.  | 
 | 
 This greater variability 
 in | in 1869 1872 |  | of 1859 1860 1861 1866 |  
  
mongrels than 
 in | in 1869 1872 |  | of 1859 1860 1861 1866 |  
  
hybrids does not seem 
 ..| ..... 1869 1872 |  | to me 1859 1860 1861 1866 |  
  
at all surprising.  For the parents of mongrels are varieties, and mostly domestic varieties (very few experiments having been tried on natural 
 | 
 
  
  
 
Hybrids
 | 
Hybrids
 1859 1860 1861 |  | 
Hybrids
 1866 1869 1872 |  
  
 
and
 | 
and
 1859 1860 1861 |  | 
and
 1866 1869 1872 |  
  
 
Mongrels
 | 
Mongrels
 1859 1860 1861 |  | 
Mongrels
 1866 1869 1872 |  
  
 
compared
,
 | 
compared
,
 1861 |  
| 
compared,
 1859 1860 |  
| 
compared,
 1866 1869 |  
| 
compared
,
 1872 |  
  
 
independently
 | 
independently
 1859 1860 1861 |  | 
independently
 1866 1869 1872 |  
  
 
of
 | 
of
 1859 1860 1861 |  | 
of
 1866 1869 1872 |  
  
 
their
 | 
their
 1859 1860 1861 |  | 
their
 1866 1869 1872 |  
  
 
fertility
.—
 | 
fertility
.—
 1859 1860 1861 |  | 
fertility
.
 1866 |  | 
fertility
.  1869 |  | 
fertility
.  1872 |  
  
 | 
 Independently of the question of fertility, the offspring of species 
 when crossed | when crossed 1859 1860 1861 1866 1869 |  when crossed 1872 |  
  
and of varieties when crossed may be compared in several other respects.  Gärtner, whose strong wish 
 it was | it was 1861 1866 1869 1872 |  | was 1859 1860 |  
  
to draw a 
 distinct | distinct 1861 1866 1869 1872 |  | marked 1859 1860 |  
  
line 
 ..| ..... 1861 1866 1869 1872 |  | of distinction 1859 1860 |  
  
between species and varieties, could find very 
 few, | few, 1861 1866 1869 1872 |  | few 1859 1860 |  
  
and, as it seems to me, quite unimportant differences between the so-called hybrid offspring of species, and the so-called mongrel offspring of varieties.  And, on the other hand, they agree most closely in 
 very | very 1859 1860 1861 |  very 1866 1869 1872 |  
  
many important respects.  | 
 | 
 I shall here discuss this subject with extreme brevity.  The most important distinction is, that in the first generation mongrels are more variable than hybrids; but Gärtner admits that hybrids from species which have long been cultivated are often variable in the first generation; and I have myself seen striking instances of this fact.  Gärtner further admits that hybrids between very closely allied species are more variable than those from very distinct species; and this shows that the difference in the degree of variability graduates away.  When mongrels and the more fertile hybrids are propagated for several 
 generations | generations 1859 1860 1861 1866 |  | generations, 1869 1872 |  
  
an extreme amount of variability in 
 their | their 1859 1860 1861 1866 |  | the 1869 1872 |  
  
offspring 
 is | is 1859 1860 1861 1866 |  
| in both cases is 1869 1872 |  
  
 notorious; | notorious; 1860 1861 1866 1869 1872 |  | notori- ous; 1859 |  
  
but some few 
 cases both of | cases both of 1859 1860 1861 1866 |  
| instances of both 1869 1872 |  
  
hybrids and mongrels long retaining 
 uniformity of | uniformity of 1859 1860 1861 1866 |  | a uniform 1869 1872 |  
  
character could be given.  The variability, however, in the successive generations of mongrels is, perhaps, greater than in hybrids.  | 
 | 
 This greater variability 
 of | of 1859 1860 1861 1866 |  | in 1869 1872 |  
  
mongrels than 
 of | of 1859 1860 1861 1866 |  | in 1869 1872 |  
  
hybrids does not seem 
 to me | to me 1859 1860 1861 1866 |  to me 1869 1872 |  
  
at all surprising.  For the parents of mongrels are varieties, and mostly domestic varieties (very few experiments having been tried on natural 
 |