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Darwin Correspondence Project

From Thomas Aitken   [c. 25 June 1874]1

Inverness District Asylum | Inverness


1st. The Pinguicula Vulgaris is found all over the North of Scotland in moist ground— The P. Alpina is got at Rise Haugh & the P. Lusitanica is I believe plentiful in the Hebrides though I have not gathered it.

2: Amongst the Patients it is most commonly known as the Brog na cuach: Cuckoo’s Boots or Spoag na cuach: Cuckoos Claw   Another called it the Lus na ima. & another Cerban an Isleible2  The two latter terms the patients could not translate. but as Im is butter in Gaelic some hidden reference either to the sensation communicated in touching the leaves of the plant, or to its use in reference to Milk may be contained in the word Lus na ima. which from the particle na I think must be a question

3. I have questioned men from every district in the Highlands & every Island almost except St. Kilda but none of them have ever heard of the Plant being used for curdling milk, & so far as I can find out it is only employed for making a decoction for, in some places, bathing wounds. but principally for applying to the Udders of Cows when they are sore. It is on the other hand held to be very injurious to sheep & to cause foot rot if eaten

I may add that I have read somewhere that the Laplanders use the Pinguicula for Coagulating Milk but I do not know of any other people who do so.3

Rennet is principally used throughout the district for curdling milk & is made from various animals. Hare Rabbit & Roe: & I have been informed that that made from the last animal is held in specially high estimation. Many of the patients have seen it done with Nettles. & even with water cresses. & an attendant mentioned that he had noticed yearned4 milk made by rubbing the inside of the dish with a large variety of “docken”5 before it was poured in   A patient who states she has seen it done with water cress. The Nettle, however, seems to have been most generally used for this purpose. all parts of the plant being suited for it— It would appear at the same time that the root had some special effect for when the Rennet becomes weak a woman well versed in Country Matters stated it was customary to add some of it to the fluid to restore it to its former strength

Thos Aitken

CD annotations

Top of letter: ‘Aitken. | Yearning means curdling | Ping is used in S. of Scotland for this purpose— | Alice Hutchinson’6 pencil


The year is established by the reference to CD’s research on Pinguicula (butterwort), and the date by the reference in an annotation to Alice Hutchison (see n. 6, below).
Lus na ima: ‘butterwort’, literally, ‘herb of the butter’ (Scots Gaelic). No translation has been found for Cerban an Isleible.
The Laplander practice of using butterwort to curdle milk was described by Carl von Linné (Linnaeus 1737, p. 10). See letter to W. T. Thiselton-Dyer, 26 June 1874, and letter from Francis and Amy Darwin, 8 August [1874]; see also Insectivorous plants, pp. 384 and 389.
Yearn: curdle; see also CD’s annotations.
Docken: Scots dialect word for docks (Rumex).
Alice Hutchison visited the Darwins from 25 to 30 June 1874 (Emma Darwin’s diary (DAR 242)).


Insectivorous plants. By Charles Darwin. London: John Murray. 1875.

Linnaeus, Carolus (Carl von Linné). 1737. Flora Lapponica exhibens plantas per Lapponiam crescentes, secundum systema sexuale collectas in itinere. Amsterdam: Salomon Schouten.


Reports that Pinguicula is found in north of Scotland. Gives local names and uses. None of his patients, who are from all parts of Scotland, has heard of the use of Pinguicula to curdle milk.

Letter details

Letter no.
Thomas Aitken
Charles Robert Darwin
Sent from
Inverness District Asylum
Source of text
DAR 58.1: 150–2
Physical description
5pp inc ? †

Please cite as

Darwin Correspondence Project, “Letter no. 9204,” accessed on 22 September 2020,

Also published in The Correspondence of Charles Darwin, vol. 22