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Darwin Correspondence Project

From John Scott   25 September 1872

Calcutta | Roy. Bot. Gardens

25th. Sept. 1872

Dear Sir,

I had fully intended sending you some notes on the worm casts (enclosed in a Kew case) shortly after their despatch, I delayed in hopes to accompany them with others from Dr. King on the casts marked S. India.1 I am indebted to him for these. He was taken very ill however and has had to leave us altogether for a year or so at home.2 Since he left I have been in charge here; but I am scarcely I fear likely to keep it until his return: the appointment is one that the medical faculty claim and 〈I〉 believe they are doing all they can to get one of their body installed. Dr. King wrote strongly in my favour and I believe the Lieut. Governor is also very favourable to me and not a few others high in office.3 I cannot hear what the Lieut Govr. intends doing; anyhow he has kept many in anxiety for the last two months and I in the meantime hold the appointment. I am thus kept very busy attending alike to my own duties and those of the Superintendent.— I shall not however delay longer in affording you the few observations I have been able to make here on worm workings.—

I am very pleased to hear th〈e〉 two notes previously sent are of interest to you.4 But I must first correct one on the wo〈rms〉 in the Rice fields. I know not how I could have made the slip to say that worms exist even in the flooded rice-fields.5 This is a serious mistake. As soon as the rains set in and the fields begin to get flooded all the worms betake themselves to the higher surrounding grounds: at least such places are greatly infested with them during the rains while in the subsequent cold and hot seasons (especially the latter) you will scarcely find one. I do not think they can live in the flooded rice-fields. 〈I〉 have been often surprised 〈by th〉em with their quick return 〈    〉 the latter after the rains 〈ha〉ve ceased, when the crops are 〈fla〉ttened and the lands dry. It is indeed wonderful to see so quickly the grounds studded with their Castings. One would almost be inclined to believe that they hybernate therein throughout the rains even as during the dry and parching weather the Land leeches and some of the smaller fish do. This however they can never do in lands full of water. This they possibly may do however: at no great depth in most of our rice-fields here occurs an impervious layer of clay. Can it be that these penetrate and remain more or less dormant in this throughout 〈the〉 rains. It is indeed difficult 〈to〉 understand how they can all reach the very limited tracts of dry land as the rains set in and so quickly as the low lands dry spread themselves so numerously over such extensive tracts. The eggs of worms are scarcely likely to survive three or four months submergence, and even should they do we have still the difficulty that full grown worms are abundant as well as those of smaller sizes.

1. With regard to the washing down of casts.—6 In the hot season, it is only in very moist and shady places as under trees and by the sides of tanks & watercourses that we find any Casts here. During the close of the rains and in the early part of the cold season you will find our lands very generally covered with them: especially so are sun lawns. They are I think on these far more serious pests than ever I saw them on lawns in Britain. About the close of the rains when they are working almost amongst plastic mud: the casts harden during the day and are very slowly denuded by rain. They are in general only rounded off and long stand up in little Knolls. On undisturbed ground you will find them thus standing until the hot season sets in when they crack and disintegrate more or less by the dry heat. Showers (which we not unfrequently have) at this season wash them much: smoothing at least all their rough surfaces and indeed unless of a very clayey nature completely disintegrating them and then we have them as a more or less rounded disc.

During the cold season when the subsoil in which the worms work is but slightly moist every shower washes down—more or less—the casts. If very heavy you will find them quite levelled, when lighter as rounded discs. In the former case I have seen a more or less circular space five inches in diameter coated over: Casts reduced to discs I have frequently measured from three to four inches across. With regard to the washing of casts on slopes: This is very evident on any of the low banks we have here. It may be well to give you measurements of these: the following will illustrate. On a slightly inclined bank in the gardens here I marked and measured several casts and had them protected or rather enclosed. One was 212in. high by 512 in circumf. (these I ought to tell you are rainy season observations on large grass-clad artificial mounds & consisting of a loamy-clay) and when washed down after several hours rain found an extended oval disc 612 in. by 312 inches: the latter being across where the cast originally stood and consisted chiefly of the rounded remains, with a very slight deposit on the three sides: all being carried down. I give you two more cases.— 1st. of one 2 in. high by 412 in circumference disc extended downwards 5 inches from the site of cast scarcely at all above. 2d. cast 2 in. high by 312 in circumference: soil carried downwards 6 inches below original cast.

Dr. King also tells me that the big casts sent you from South India are soon washed wholly down from the mountain sides during the rains. You will observe how those (which I sent you) are rounded off. These were collected during the hot season and had been chiefly disintegrated by the sun and rounded by light showers.

This leads to your second query and indeed partly answers it. I refer to the disintegration of the casts during the dry season. On fully exposed lands this is very marked and I have over and over again observed casts largely disintegrated and quite in a condition for dispersion by wind. In the hills in South India, Dr. King also observed those big casts in a similar state during the dry season. I am sure this is also the case in the mountains of Sikkim and indeed I suppose it must be so everywhere unless on exceedingly tenacious clays: seeing that it occurs in the strong clays of Lower Bengal.

3. I have oft during the last hot season when our worms apparently bore deepest (unless indeed they as I hinted might reside during the rains in the impervious layer of our rice-fields) and I have in no instance found them at more than 212 feet. The soil there is quite moist [illeg] Bengal soil all through the hot season. I do not think the worms there however are at all active; as nearly every one which I have turned up had itself coiled up in the way one often finds those at home.— I may here note that some of the worm casts which I have measured this rain are much larger than any of those of which I sent you specimens: the following are examples:— 6 inches high by 412 in circumf. 2d. 5 inches high by 612 in circumf. 3d. 5 in. high by 8 in circumf. Generally they are from 34 or 5 inches high by 4 in girth. These are evidently cast up in a single night and those of the largest size noted above could not from the appearance of the clay be more than the work of two nights and this from a single worm. They are thus by no means mean agents in the transposition of matter. They also swarm everywhere almost in Bengal, and I presume elsewhere in India.

The casts sent you with the exception of those marked S. India are all from Lower Bengal.

You will observe the little pellets: these take the place generally speaking of casts in dryish grounds. Thus on our walks and under trees where the soil is dry and loose you will find the ground around the worm holes strewed with pellets of various sizes: very rarely do you observe casts as on wet grounds. In forests here generally speaking worms are less abundant than on open grounds. They affect them the most during the hot weather as might be expected. These pelled are washed away with every shower and disintegrate readily in the dry season. They vary as you will see by the specimens sent greatly in size.

4. The only query that remains I think regards worms drawing leaves into the mouths of their burrows. This they do here even as in temperate climates. This is chiefly however in the cold weather: in the mornings you everywhere meet with worm holes with leaves and twigs filling their mouth. During the rainy season I have rarely observed this. Pebbles I have never seen but I have had no opportunity of observing their habits in districts where these occur and here they would search in vain for such.

I do not think that I can give you any more information regarding these, but should anything have escaped me, or there be any other observations that you should like made it shall be a great pleasure to me to hear them. It is highly gratifying to me to hear from you that any little observations of mine are of value.

I am just now getting up a paper (very fully illustrated) on palm-stem structure. I have also one nearly finished on the structure of the stem of the Common Papaya—Carica papaya—I have also some interesting matter on sexual changes and reproduction of varieties in it.7 I am getting a bisexual race of it established.

I am exceedingly sorry to see by the papers that Dr. Hooker should have been so tyrannised over by Mr. Ayrton! it is pleasing to see however the general sympathy his case has evoked.8

I am | your obliged & faithful svt | John Scott.

CD annotations

1.1 I had … doing all they 1.7] crossed blue crayon
2.2 in the Rice fields] scored blue crayon; ‘〈    〉 in flooded field’ blue crayon
2.8 in the flooded rice-fields.] closing square bracket blue crayon
2.21 as well] underl blue crayon
6.1 This leads] after opening square bracket, red crayon
7.6 I may here note … girth. 7.10] crossed pencil
10.1 4.] ‘4’ blue crayon, circled blue crayon
11.2 or … evoked 13.3] crossed blue crayon
On cover: ‘John Scott | Habits & action’ pencil
On CD note:
3.1 Error … dry. 3.6] crossed pencil
3.2 very soon] double underl blue ink
5.3 Harden … disc.— 5.6] double scored red crayon
5.4 Crumble … Heat] underl red crayon
5.4 Showers … wash 5.5] underl red crayon
5.5 less rounded disc.— 5.6] underl red crayon
8.1 Second … Sikkim 8.2] scored red crayon
9.1 p. 3 (b) … done— 13.2] crossed blue crayon

CD note:

Abstract of J. Scott on Worms. Sept 25/72/9

p. (1)

Error in last letter. *Very soon [interl] After the water has disappeared from the Rice field, the surface is studded with full-sized [interl] castings. Also very soon after the Rice-fields *are dry [blue ink above del ‘are flooded’] the *surface studded with [interl blue ink] castings [‘appear, but being [illeg] than before,’ del] in very [interl] large numbers on any small [above del illeg] tract which remains dry. Mr Scott does not know whether the worms migrate from the flooded tracts, or penetrate deep into the underlying clay & there become dormant, & reappear as soon as the surface becomes dry.

(The castings from S. India collected by Dr King) [square brackets in MS]

p. 2. No castings during Hot-season *except shady places & near tanks [interl].— at close of wet season & dry cold season the land covered with castings, especially on Lawns— thinks more abundant or numerous— Harden during day & are very slowly denuded— generally only rounded off & long stand up as little Knolls.— afterwards [interl] Crumble & disintegrate more or less by dry Heat.— Showers at this season wash them much & if not of very clayey nature quite disintegrate them, & form more or less rounded disc.—

During cold-season when the castings are rather dry, every shower washes them down more or less— if showers are [interl] very heavy they are quite levelled, if less Heavy they are formed into a rounded disc.— Have seen in former case *(ie after Heavy showers [interl] a space of 5 inches in diameter coated over.— Has often measured others 3– to 4 in diameter.—

It is very evident the washing down of the castings on *such low banks as they have in Gardens [interl, pencil] slopes.— (see p. 2.[interl] C) *actual measurements given [added above]— Also Dr King (p. 3) on the washing down of the big-castings *disintegrated by the sun & rounded by light showers [interl blue ink]. Washed down the mountain-sides during rains.—

Second-query p. 3. disintegration of casts during dry season— this is very marked. & ready for dispersal by wind.— do also Dr King. saw them in similar st〈ate〉 during dry season— do in Sikkim   p. 3 measurements of casts

p. 3. (b) has never seen worms below 212 feet deep, where it is damp all through the hot season. & worms then seem torpid.

p. 3 (c) size of great castings — many measurements. *(Have I used these measurements, I could work them in at end of ch 1.) [interl blue ink; square brackets in MS]— in single night.! or 2 nights.— swarm everywhere in Bengal.

All the castings sen〈t〉 from Lower Bengal.—

Pellets on dry ground.— — In forests less abundant than on open ground— Most in former sites during hot weather.— These pellets washed away every shower, & *disintegrate readily [underl red crayon] during dry season.— [double scored blue crayon]

p. 4. Worms draw leaves *and twigs [interl] into Holes, as in temperate climate.— chiefly during the cold *& dry [interl] season. During rainy season rarely done—

Footnotes

The worm castings collected by Scott and George King had arrived at the Royal Botanic Gardens, Kew, without an accompanying letter (see letter to John Scott, 12 August 1872 and n. 1, and enclosure to letter from J. D. Hooker, 29 August 1872).
King, the superintendent of the botanic gardens in Calcutta, had returned to England on medical leave (see enclosure to letter from J. D. Hooker, 29 August 1872, and letter from J. D. Hooker, 26 October 1872).
The lieutenant-governor of Bengal was George Campbell (India list 1872).
Only one previous letter from Scott on worms has been found (see letter from John Scott, 22 March 1872). CD acknowledged this and requested more information in his letter of 15 April [1872]. Scott’s observations are reported in Earthworms, pp. 123–6.
No papers by Scott on these topics have been found.
For more on the dispute between Joseph Dalton Hooker and Acton Smee Ayrton, see the letter to J. D. Hooker, 4 August [1872] and n. 1.
The abstract of Scott’s letter was evidently made because CD had difficulty reading the original (see letter to John Scott, 26 October 1872).

Summary

Acting as Superintendent of Royal Botanic Garden, Calcutta.

Observations on worm-castings in India.

Letter details

Letter no.
DCP-LETT-8534
From
John Scott
To
Charles Robert Darwin
Sent from
unstated
Source of text
DAR 177: 121
Physical description
14pp, CD note †

Please cite as

Darwin Correspondence Project, “Letter no. 8534,” accessed on 16 February 2019, http://www.darwinproject.ac.uk/DCP-LETT-8534

Also published in The Correspondence of Charles Darwin, vol. 20

letter