of the _Origin_, but it has a certain freshness
which gives it a character of its own. It must be remembered that the
_Origin_ was an abstract or condensation of a much bigger book, whereas
the Essay of 1844 was an expansion of the sketch of 1842. It is not
therefore surprising that in the _Origin_ there is occasionally evident
a chafing against the author's self-imposed limitation. Whereas in the
1844 Essay there is an air of freedom, as if the author were letting
himself go, rather than applying the curb. This quality of freshness and
the fact that some questions were more fully discussed in 1844 than in
1859, makes the earlier work good reading even to those who are familiar
with the _Origin_.

The writing of this Essay "during the summer of 1844," as stated in the
Autobiography{30}, and "from memory," as Darwin says elsewhere{31}, was
a remarkable achievement, and possibly renders more conceivable the
still greater feat of the writing of the _Origin_ between July 1858 and
September 1859.

{30} _Life and Letters_, i. p. 84.

{31} _Life and Letters_, ii. p. 18.

It is an interesting subject for speculation: what influence on the
world the Essay of 1844 would have exercised, had it been published in
place of the Origin. The author evidently thought of its publication in
its present state as an undesirable expedient, as appears clearly from
the following extracts from the _Life and Letters_, vol. ii. pp.
16--18:

_C. Darwin to Mrs Darwin._

DOWN, _July 5, 1844_.

"... I have just finished my sketch of my species theory. If, as I
believe, my theory in time be accepted even by one competent judge, it
will be a considerable step in science.

"I therefore write this in case of my sudden death, as my most solemn
and last request, which I am sure you will consider the same as if
legally entered in my will, that you will devote L400 to its
publication, and further will yourself, or through Hensleigh{32}, take
trouble in promoting it. I wish that my sketch be given to some
competent person, with this sum to induce him to take trouble in its
improvement and enlargement. I give to him all my books on Natural
History, which are either scored or have references at the end to the
pages, begging him carefully to look over and consider such passages as
actually bearing, or by possibility bearing, on this subject. I wish you
to make a list of all such books as some temptation to an editor. I also
request that you