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 generation 
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. levis (Bertoloni, not Linnzeus), and D. tatula, three 
very constant forms which had previously been regarded as good 
Species. By adding to these the D. tatula inermis, 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. Ido 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 meaus 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, 
