>>I am reposting this from sci.bio.evolution; it makes a nice "reality
>>check" for Ev Cochrane's ridiculous claim that Darwin was an
>>"enthusiastic" supporter of inheritance of acquired characteristics.
>>Explanatory note: the possibility of such inheritance was _one_
>>feature of Darwin's "pangenesis" theory of heredity.  To the best of
>>my recollection, Darwin's invocations of "use and disuse" to expalin
>>specific adaptations, outside the context of his discussions of
>>pangenesis (the latter, as noted, NOT being in the _Origin_), are
>>limited to the notorious flatfish example mentioned below.
 
>>>>     I read "Origin of Species" very carefully, and I never saw any
>>>>mention of pangenesis and blood transfusions of rabbits.  Maybe it was
>>>>something in his lab notebooks.  If so, the experiment made him reject
>>>>pangenesis.  Furthermore, although he admits to the possibility of
>>>>"inheritance of acquired characteristics," he says that that is a minor
>>>>effect and not generally important.  Random mutations, not acquired
>>>>characteristics, are the main material of Darwin's evolution.  He only
>>>>uses the acquired characteristics to explain flatfish, an atypical
>>>mistake.

The far more interesting and significant quotation of Darwin appears on 
page 12 of the VIth edition of _The Origin_ "The laws of inheritance are
for the most part unknown."  However, Darwin does advance 'use and disuse'
as on page 10 with "Changed habits produce an inherited effect as in the
flowering of plants when transported from one climate to another."  He
then goes on to add some of the examples that Ev follows with:


> "I think there can be little doubt that use in our domestic animals
> strengthens and enlarges certain parts, and disuse diminishes
> them; and that such modifications are inherited." (p. 134).

This is on page 128 in edition VI.

> Darwin concludes his chapter by writing as follows:
>  
> "We may conclude that use, and disuse, have, in some cases,
> played a considerable part in the modification of the constitution,
> and of the structure of various organs..." (p. 143)

But on page 157 of my copy, Darwin writes, "Whatever the cause may be of 
each slight difference between offspring and their parents -- and a cause
for each must exist -- we have reason to believe that it is the steady
accumulation of beneficial differences which has given rise to all the
more important modifications in relation to the habits of each species." 
This is at the end of Chapter V, "Laws of Variation." 

At the start of this summary, page 155, Darwin writes, "Our ignorance
of the laws of variation is profound.  Not in one case out of a hundred
can we pretend to assign any reason why this part or that part has varied."

He continues (I skip a sentence or so), "Changed conditions generally 
induce more fluctuating variability, but sometimes they cause direct and
definite effects; and these may become strongly marked in the course of
time, though we have not sufficient evidence upon this head."  (Yes, the
sentence ended, 'upon this head.')

I have skipped around a bit and pulled sentences out of context but it
does not distort the meaning.  As Mayr writes in _One Long Argument_,
"It is frequently stated that Darwin totally rejected all Lamarckian
ideas in the first edition of the _Origin_ and that he allowed at
that time no mechanisms of evolution other than random variation and
natural selection.  This is not correct.  Darwin displayed considerable
indecision already in 1859 on the origin of variation and the nature
of inheritance" (page 109, OLA).  

I am far from being a scholar on the matter of Darwin and his writings
but it seems only logical to place more emphasis upon his later writings
that his first.  Mayr's characterization of 'considerable indecision'
comes across very clearly and it probably worked for Darwin because
Darwin felt no pressing responsibility to define a mechanism of
inheritance.  And, perhaps, his greatest concern was for the aspect of
science in the early 1800's that considered blending of inheritance
to be a major problem with transmitting altered characteristics into
following populations by reproduction of preceeding generations.

Therefore, I think my e-friends Steve and Ev are both right and wrong.
Darwin did cite use and disuse in a Lamarckian fashion (one up for Ev)
(though Steve did acknowledge that was _one_ of Darwin's points).

Bit it was not likely Darwin's main purpose (one up for Steve) was to
provide an authoritative theory of inheritance.  Darwin was out to 
discuss natural selection but because he found natural selection acted
on *inherited* variations, he had to connect to the current theories 
of inheritance and Lamarckian use and disuse was all there was at the
time.

An interesting speculation is perhaps, "what would Charles Darwin have
thought if he had learned of the experiments of Mendel or of our modern
understandings of genetics and mutation?"  Surely, Darwin would have been
interested and likely thrilled.  If modern genetics has falsified 
use and disuse as a means of inheritance, Darwin would not have had to 
change his ideas on whit.

Earlier Rosen mentioned mutation as being part of an explanation of 
Darwinism.  Of course, that is understood now but Darwin had no knowledge
of mutation did he?  He does refer to 'monstrosities' at times but even
if he had an inkling of the genetic bases of those, it seems very unfair
to implicate any understanding of the intricate and sometimes delicate 
effects mutation can have in providing bases of variation for natural
selection and evolution.

What is of even more importance than this debate about the history of
ideas is what science says about the mechanisms of inheritance today.
Clearly, Darwin referred natural selection to inheritance, but he did
not tie natural selection to any one mode or mechanism of inheritance. 
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