Ɛpsilon

From Lawson Tait   31 December [1877]1

Birmingham

Decr. 31

My Dear Sir,

I believe I have made a discovery which will greatly interest you   It is no less than the method by which tails are lost and I have found evidence of the process in man which I think will prove as weighty as “Darwin’s ears” is in another direction.2 It is too long a matter for me to go into now but let me merely say that the process is the occurrence of spina bifida and the remnant in man of the process consists of depression of the skin over the point of the coccyx & its union (by fascial adhesion) to the post. surface of the tip bone. I have been engaged all morning in making casts of the depressions in a family of children who have it marked in all & very marked in one. The mother has it. The very marked one I try to give you an idea of in the diagram below. The depression is tubular & quite half an inch deep3

Yours truly | Lawson Tait

diagram

child aged 6 12

I think it quite on a par with the pharyngeal fistula which indicates the lost bronchial opening & the labial furrow which shows the lost hare-lip.4

LT

I’ll send you a cast5

1
The year is established by the reference to the discovery of the sacral dimple. The results of the investigations described in this letter were published in 1878 (see n. 3, below).
2
Tait refers to what CD called the ‘Woolnerian tip’, discussed in Descent 1: 22–3, and in greater detail in Descent 2d ed., pp. 15–17. The sculptor Thomas Woolner’s drawing of a human ear showing the unusual feature of a pointed tip (‘Woolner’s tip’) on the outer ear projecting from the inwardly folded margin is in DAR 80: B120.
3
Tait described his discovery of a depression over the lowest bone of the sacrum in this family in ‘Note on the occurrence of a sacral dimple and its possible significance’, a paper read at the meeting of the British Association for the Advancement of Science in August 1878 (L. Tait 1878).
4
A pharyngeal fistula is a congenital fistula in the neck resulting from incomplete closure of a pharyngeal groove or cleft. The labial or nasolabial furrow is the major facial furrow that extends from the side of the nose downward and outward to a point just below the outer corner of the mouth, often called a smile or laugh line.
5
Tait deleted the beginnings of a second sketch at the end of the letter and wrote ‘failure’ across it.

Please cite as “DCP-LETT-11297,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11297