tly considered this as more important
than the inheritance of habit or other acquired peculiarities.

Another point of interest is the weight he attached in 1842-4 to
"sports" or what are now called "mutations." This is I think more
prominent in the _Foundations_ than in the first edition of the
_Origin_, and certainly than in the fifth and sixth editions.

Among other interesting points may be mentioned the "good effects of
crossing" being "possibly analogous to good effects of change in
condition,"--a principle which he upheld on experimental grounds in his
_Cross and Self-Fertilisation_ in 1876.

In conclusion, I desire to express my thanks to Mr Wallace for a
footnote he was good enough to supply: and to Professor Bateson, Sir W.
Thiselton-Dyer, Dr Gadow, Professor Judd, Dr Marr, Col. Prain and Dr
Stapf for information on various points. I am also indebted to Mr
Rutherford, of the University Library, for his careful copy of the
manuscript of 1842.

CAMBRIDGE,

_June 9, 1909._

EXPLANATION OF SIGNS, &c.

[] Means that the words so enclosed are erased in the original MS.

<> Indicates an insertion by the Editor.

_Origin_, Ed. vi. refers to the Popular Edition.

PART I.

Sec. I. <ON VARIATION UNDER DOMESTICATION, AND ON THE PRINCIPLES OF
SELECTION.>

An individual organism placed under new conditions [often] sometimes
varies in a small degree and in very trifling respects such as stature,
fatness, sometimes colour, health, habits in animals and probably
disposition. Also habits of life develope certain parts. Disuse
atrophies. [Most of these slight variations tend to become hereditary.]

When the individual is multiplied for long periods by buds the variation
is yet small, though greater and occasionally a single bud or individual
departs widely from its type (example){36} and continues steadily to
propagate, by buds, such new kind.

{36} Evidently a memorandum that an example should be given.

When the organism is bred for several generations under new or varying
conditions, the variation is greater in amount and endless in kind
[especially{37} holds good when individuals have long been exposed to
new conditions]. The nature of the external conditions tends to effect
some definite change in all or greater part of offspring,--little food,
small size--certain foods harmless &c. &c. organs affected and
diseases--extent unknown. A certain degree of variation (Mueller's
twins){38}