Sent E. Warren to K. Pearson, 12th March 1899.
12 Mar 1899
Description:

‘Dear Prof. Pearson,

Many thanks for your note re: the relative variability of sexual and parthenogenetic generations.

I am sending a note to the Royal comprising the observations on Daphnia and therein stating that I am about to test the theory on some other parthenogenetic animal.

The Daphnia results certainly tell against Weismann’s views at least in an unmodified form. If I understand Weismann correctly the offspring in a brood produced by parthenogenesis should exhibit little or no variability or as you say drones should be much alike to one another. In the Daphnia the offspring of a parentage of 169.5 thousands possessed a range of variation from 159.5-181.5 while the total range of all the offspring (i.e. of all the 96 individuals) was 159.5-185.5 thousands. Thus although the coeffts. of correlation and regression were respectively .466 and .619 yet the individuals of the same brood showed very considerable variability.

Bees would be good things to measure (- at least so I should think) but there is a difficulty with regard to the origin of the drones. Apparently in a hive if there happens to be a scarcity of drones some of the workers will produced [sic] males parthenogenically!! Thus in any population of drones some may have been produced by parthenogenesis by the Queen & some by the usually barren workers.

With regard to the increase of variability with parthenogenesis. My results apparently show that the S.D. of offspring is greater than that of parents & so with a correlation of .4 the regression is .6 & the parthenogenetic mother acts, so to speak, like a mid-parent. It is this that I hope to test on a new beast. Aphis (the greenfly) seems a favourable creature for the purpose but it is doubtful whether it would be practicable to obtain sexual generations to compare with the parthenogenetic ones. There are about 10 parthenogenetic generations than winged sexual forms are born & these lay eggs which hatch out parthenogenetic females.

I am sincerely sorry that your recovery is so slow.

Yours very faithfully,

E. Warren.

P.S. It is the apparent increase of variability as we pass from one parthenogenetic generation to another that puzzles me. It is very antagonistic to Weismann.’

Sent E. Warren to K. Pearson, 12th Nov. 1898.
12 Nov 1898
Description:

‘Dear Prof. Pearson,

I am sending you the results of my measurements on the bones.

Femur 1 and 2 of Naqada Race behave almost identically.

Max. diff between the dry and soaked bone is in both cases 2.2 mm. In the first 24 hours they expand 1.7 mm and in the next 4 days only about 0.5 mm.

On removing from the water the most rapid contraction takes place between the 2nd & 3rd days.

And the maximum rate of 2.6 mm to 1.7 mm for T.[?] expansion is reached in the first hour or two and then gradually diminishes while the max rate for contraction is not reached before about the 2nd or 3rd day.

The effect of soaking on the modern bones is very slight. It is somewhat less than 1 mm in both tibia and femur.

I should add that on drying the Naqada bones cracked spontaneously but this apparently did not affect the length.

Yrs very truly,

E. Warren.’

[measurement tables attached]

Sent E. Warren to K. Pearson, 24th June 1896.
24 Jun 1896
Description:

 

‘Dear Professor Pearson,

I am about to apply for the Lectureship in Biology at Charing X hospital the post has been rendered vacant by the death of W. Pollard. Prof. Weldon thought that very likely you might be so good as to give me a testimonial, if you would do so I should be very grateful.

Have done as much to my crabs as I am able & am now worrying at the bones, but I fear I shall be unable to sex sufficient to form a satisfactory correlation surface. I imagine that at this busy time of the term you have not had leisure to look over Rollet’s measurements, when you do so I should be delighted to hear the result.

With kind regards,

I remain,

Yrs very faithfully,

E. Warren.’

Sent E. Warren to K. Pearson, 26th June 1896.
26 Jun 1896
Description:

‘Dear Prof. Pearson,

I thank you very much for your testimonial & letter.

I do not quite like the idea of facing another home[?] just at present. Prof. Thane is going to attempt to sex the saera & hip bones, the latter very unfortunately are mostly broken into fragments. In any case the determinations ought to give some idea as to the accuracy of the skull & long bone sexing.

From the appearance of the bones I believe, excepting the 9[?] graves etc[?], that there is but one race.

I will ascertain as to the Whitechapel long bones; I think there are a considerable number but certainly not as many as Libyan & so I do not see how they could help us. It would be very valuable if such a splitting up as you suggest could be effected. I wish I had a sufficiently mathematical head to attack the problem.

I remain,

Yours very faithfully,

E. Warren.’

Sent E. Warren to K. Pearson, c.19th Jan. 1903.
19 Jan 1903
Description:

‘Dear Prof. Pearson,

The thickness of the shell of snails varies very considerably and I have been wondering whether this might not be a character which could be readily measured in addition to the “radula” teeth.

There is a little instrument made by Zeiss for measuring the thickness of cover-glasses for microscopic slides, and I should think it could readily be used for little pieces of shell broken off say about half an inch above the growing edge of the snail-shell.

Undoubtedly the thickness of the shell depends to a large extent on the amount of mineral matter obtained by the animal, but the parents were procured from the same locality, and the families are living as nearly as possible under the same conditions.

Besides the snails there are several little matters I should like to talk over when you have a spare half-hour...’

Sent E. Warren to K. Pearson, c.19th Jan. 1903.
19 Jan 1903
Description:

'Dear Prof. Pearson,

One important thing I forgot to mention just now. I think it is necessary that Miss Radford should take some measurements which would give some conception of the size of the snail from which the radula was taken.

I suggest either:

(1) some measurement on the shell

(2) or the greatest diameter of the radula.

Possibly both (1) and (2) would be desirable.

For (1): (a) the greatest diameter of the mouth, (b) the distance between the apex of the shell and one corner of the mouth.

Could you think over this matter?

Yours very faithfully,

E. Warren.’

Sent E. Warren to K. Pearson, [July-Sept.] 1902.
Between Jul and Sep 1902
Description:

‘Dear Prof. Pearson,

Many thanks for your letter.

The snails you sent me – I have not identified as yet, for the book I wished to refer to is unobtainable from the library at present: the library people saying they are making great alterations. They are very pretty little things and appear to feed on lettuce with great enjoyment. Of H. aspersa I have separated one minute individual from some 38 families. These I hope to breed up to maturity and then if they produce fertile eggs they must be self-fertilised. With these inds. I have placed one of the new species of snails and so labour is economized. The new snails are very variable in the tint of the shell and in some two inds. The prominent dark band is absent. I hope that these may produce families. If by any chance when the baby H. aspersa grow up they should copulate with the other species it would be very fine to have hybrid offspring.

The H. aspersa are too fertile! The families range from 45-179. I have some 80 families in all and it is a hopeless business to attempt to keep the families so large. Already I have reduced the majority of them to 100. What do you think of reducing them to 30? I should be very glad if you would kindly give me your opinion on this rather important point.

...’

Sent E. Warren to K. Pearson, [March/April] 1897.
Between Mar and Apr 1897
Description:

‘Dear Prof. Pearson,

I thank you much for your kind letter; I was sorry to hear of Miss Lee’s indisposition.

I will do as you suggest and finish off the Libyans; it is time, I think, that I should bring them to some kind of conclusion, especially if they are to serve for the D.Sc. examination in June.

I should be very grateful, however, if you would send me the means of the French measurements which are already calculated. In a proof-sheet you formerly sent me (& which I burnt) these means were given for the French femur etc & also for some bones of prehistoric man.

Do you happen to know if there are any long-bone measurements for the “Algerians” & the skulls according to Prof. Petrie compare closely with those of the New Race. It would be interesting to see if there is any connection as regards the length of limb.

With many thanks for your kindness.

I remain,

Yrs very truly,

E. Warren.’

Sent E. Warren to K. Pearson, [Oct.-Nov. 1900].
Between Oct and Nov 1900
Description:

‘Dear Prof. Pearson,

Very many thanks for your last four papers: many of the general results have interested me greatly. That fertility and general fitness to live should go hand in hand is a very important fact for the biologist and no proof of it has been offered before.

Since, unfortunately, so many organic characters cannot be measured with any precision your new methods of dealing with such will be most valuable.

...’

Sent E. Warrent to K. Pearson, 8th July [1902?].
8 Jul 1902
Description:

‘Dear Prof. Pearson,

I have now counted 472 daisies (Bellis perennis (L.)) and I propose to count another series from the same patch of grass in the autumn. The modes at 34 and 42 are still more pronounced. The frequencies are:

[list of figs.]

I would be very interesting to compare this series with material gathered from various localities.

With regard to H. [sic –prob. Cepaea] hortensis, I do not know whether you have gone into the colour markings at all; but from the sample you gave me the colour variation seems to me to be very remarkable.

The shell is either lemon yellow or pale brown with no obvious bands or the shell has a whitish ground with 5 distinct dark brown bands.

[diag of each of these, w. ennumeration of pop. distribution]

Thus the shells are sharply divided into two quite distinct groups “I” and “II”; and out of 146 mds[?] I never had any doubt as to how to place any given individual.

There appears to be no transitional stages between the two groups and the case seems comparable to eye-colour etc.

If you have an opportunity to observe another population it would be most interesting to compare with the Gloucestershire series. Perhaps, however, the matter has already received your attention.

My H. aspersa[?] families are getting on very well.

Yours most faithfully,

E. Warren.'