ON VARIETIES, RACES, SXTB-SPECIES, AXD SPECIES. 93 



the case of wliich we speak should not be excluded therefrom. 

 Then, if the rjuestion should relate to hybritls capable of lepro- 

 duction through an indefinite number of generations, we shall 

 have a species, not, according to our. view, originating with a 

 male and female of different species, but with the first hybrid, 

 because that is in fact the first type of the form found in its de- 

 scendants. 



After these general considerations on hybrids, we will only 

 add, that the study of hybridizing is far too much neglected, 

 notwithstanding the splendid results obtained by those wlio, like 

 Sageret, Duchesne, Knight, &c , have really paid attention to 

 the subject. Let it not be forgotten that tlie former gentleman 

 obtained from different species of apple, hybrids, which by their 

 great vigour allow the fruit of one season to ripen whilst the flower- 

 buds of the next are being developed, thus insuring a good crop 

 the following season without any alternation or without ceasing to 

 bear for a year or two after every crop ; let it not be forgotten that 

 the same gentleman obtained some very remarkably prolific sub- 

 hybrid apple-trees, and then let not the study of hybridizing be 

 set down as vain, or without any practical or useful bearing. 



§ IV. — CONSEQUENCES OF THE FOREGOING FACTS WITH REGARD 

 TO THE QUESTION OF THE FIXITY OF VEGETABLE SPECIES 

 UNDER PRESENT CIRCUMSTANCES. 



Although there are living bodies which undergo great modi- 

 fications from external agents (§ 3), and which preserve them 

 when the causes by which they were produced are removed, it 

 is evident, from the details into which we have entered, that 

 most of such bodies tend to lose their modifications under these 

 circumstances, and to reassume the primitive form of their re- 

 spective species ; or, what is more correct according to our defi- 

 nition, the most stable form which the living body can take 

 under the circumstances when it has lost its modifications. 



Every one who has paid any attention to the modifications of 

 plants, must have been struck with the great stability of a cer- 

 tain form which all the individuals of one species tend to assume ; 

 this fundamental fact, this power of nature to retake possession 

 of plants which by long culture have taken new forms, was 

 especially noticed by M. Vilmorin and M. Poiteau. 



Van Mons believes so firmly in the principle of the stability 

 of species, that, in his opinion, the modifications produced in 

 plants by cultivation, only reach those individuals which repre- 

 sent the types of their respective species ; for, according to him, 

 each of the groups of plants altered by cultivation to which 

 such names as beurre, bon chretien, are given, comprise indivi- 



