In 1861 that botanist observed, amongst a sowing of _Datura tatula_, the fruits of which are very spinous, a single individual of which the capsule was perfectly smooth.

The seeds taken from this plant all furnished plants having the character of this individual.

The fifth and sixth generations are now growing without exhibiting 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 original types, as true hybrids do." There are, then, abundant instances to prove that considerable {102} modifications may suddenly develop themselves, either due to external conditions or to obscure internal causes in the organisms which exhibit them.

Moreover, these modifications, from whatever cause arising, are capable of reproduction--the modified individuals "breeding true." The question is whether new species have been developed by non-fortuitous variations which are insignificant and minute, or whether such variations have been comparatively sudden, and of appreciable size and importance?
Either hypothesis will suit the views here maintained equally well (those views being opposed only to fortuitous, indefinite variations), but the latter is the more remote from the Darwinian conception, and yet has much to be said in its favour.
Professor Owen considers, with regard to specific origination, that natural history "teaches that the change would be sudden and considerable: it opposes the idea that species are transmitted by minute and slow degrees."[92] "An innate tendency to deviate from parental type, operating through periods of adequate duration," being "the most probable nature, or way of operation of the secondary law, whereby species have been derived one from the other."[93] Now, considering the number of instances adduced of sudden modifications in domestic animals, it is somewhat startling to meet with Mr.Darwin's dogmatic assertion that it is "a _false belief_" that natural species have often originated in the same abrupt manner.