Miscellaneous. 143 



found in a sowing of Datura tatula, a species with very spinous 

 fruits, a single individual of which the capsule was perfectly smooth 

 and unarmed. The seeds taken from this capsule furnished, in 1862, 

 a lot of plants, all of which faithfully reproduced the individual from 

 which they were derived. From these seeds sprang a third genera- 

 tion similarly unarmed ; and I have myself observed at the Museum, 

 in 1865 and 1866, the fourth and fifth generations of this new race, 

 in all nearly one hundred individuals, none of which manifested the 

 least tendency to resume the characters of the spinous type of the 

 species. When crossed with the latter by M. Godron himself, the 

 unarmed race furnished hybrids, which in the succeeding generatioa 

 reverted to the spinous and unarmed forms ; in other words, they 

 behaved like true hybrids endowed with fertility. From this fact 

 M. Godron proceeds to refer to a single specific type Datura stra- 

 monium, D. l<cvis (Bertoloni, not Linnseus), and D. tatula, three 

 very constant forms which had previously been regarded as good 

 species. By adding to these the D. tatula ineniiis, discovered by 

 him, and to a certain extent originated under his eyes, we have four 

 distinct forms, issuing by variation from a single type, and with 

 regard to which we should not well know how to say what they 

 wanted of being true species. 



Here a point presents itself to which I call the particular atten- 

 tion of those who believe in the mutability of specific forms, and 

 ascribe the origin of existing species to simple modifications of more 

 ancient ones. They assume (at least most of them do so) that 

 these modifications have been effected with excessive slowness, 

 and by insensible transitions — for example, that it required 

 several thousands of generations to transform one species into 

 another congeneric species. We do not know what may have 

 taken place in this long lapse of ages ; but experiments and observa- 

 tion teach us that in the present day slight or profound anomalies, 

 alterations of what we, perhaps arbitrarily, call specific types, — in a 

 word, monstrosities, whether they be transitory and purely indi- 

 vidual, or give rise to new durable races uniform in an unlimited 

 number of individuals, are produced suddenly, and without there 

 ever having been transition forms between them and the normal 

 form. A new race originates perfectly formed, and the first indi- 

 vidual which represents it is at once such as it will show in the suc- 

 ceeding generations if circumstances allow it to be preserved. New 

 modifications may be added to the first and subdivide the primary 

 race into secondary races, but they are produced with the same 

 suddenness as the first. 1 do not here set myself up as the defender 

 of the doctrine of evolution ; I only say that the biological pheno- 

 mena of the period in which we live by no means justify the hypo- 

 thesis of an insensible degradation of ancient forms and the necessity 

 of millions of years for changing the physiognomy of species. To 

 judge from what we know, these transformations, if they have taken 

 place, may have been effected in a lapse of time incomparably 

 shorter than has been supposed. It may be, indeed, that there are 

 these alternations in the life of nature — that periods of immobility. 



