XVI.] THE LAWS OF VARIATION. 197 



varieties of plants are mentioned on the authority of 

 M. C. ISTaudin i : — " The first case mentioned is that of a 

 poppy, which took on a remarkable variation in its fruit — Popp}-. 

 a crown of secondary capsules being added to the normal 

 central capsule. A field of such poppies was grown, and 

 M. Goppert, with seed from this field, obtained still this 

 monstrous form in great quantity. Deformities of ferns Ferns. 

 are sometimes sought after by fern-growers. They are 

 now always obtained by taking spores [seeds] from the 

 abnormal parts of a monstrous fern ; from which spores 

 ferns presenting the same peculiarities invariably grow. . . . 

 The most remarkable case is that observed by Dr. Godron, 

 of Nancy. In 1861 that botanist observed, amongst a 

 sowing of Datura tatula, the fruits of which are very Batura 

 spinous, a single individual of which the capsule was per- 

 fectly smooth. The seeds taken from this plant all fur- 

 nished plants having the character of this individual. The 

 fifth and sixth generations are now growing without ex- 

 hibiting the least tendency to revert to the spinous form. 

 More remarkable still, when crossed with the normal 

 Datura tatula, hybrids were produced, which, in the second 

 generation, reverted to the two original types, as true 

 hybrids do." 



The last statement may be compared with what has 

 been mentioned above, as to the impossibility of obtaining 

 a breed intermediate between the common and the otter 

 sheep. 



Very little is known about the laws of variation. We 

 may, however, make the following statements with con- 

 fidence : — 



Variation is not always going on, nor does it go on in Only some 

 every part of an organism at once. Many races produce yailabir 

 hardly any variations ; and, among the variable ones, some and some 

 characters are more variable than others ; and when a of those. ^ 

 character has recently varied, it is apt to continue variable, 



1 Quoted from the Comptes Rendus, in the Quarterly Journal of Science, 

 October 1867, p. 527. 



