# From William Turner   3 January 1870

6 Eton Terrace | Edinburgh

Janr. 3d. 1870

My Dear Sir

Kölliker of Würzburg and Langer of Vienna are the best authorities on the development of the mammae & the glands of the skin.1

They both agree in describing the mammary gland as developed before the nipple—2 Kölliker figures in a 5 months human embryo the first indications of a mamma, and the horny layer of the epidermis is prolonged over its surface without any appreciable elevation corresponding to a nipple—3

Langer states that a distinct lens shaped body may be recognised in the mammary region of a human embryo, 7$\frac{1}{2}$ centimetres long, which is the rudimentary gland, but at this early stage no trace whatever of mammary ducts can be recognized in it—4

In a female human embryo 10 centimetres long, he could not trace mammary ducts in the lens shaped body—

When hair first begins to protrude through the skin of the embryo then the mammary ducts may be seen in different stages of development.

Langer concludes that the first development of the mammary gland is connected with the existence of a special body, in which the ducts arise independently, & are not involutions of the external skin—

At first the ducts possess one common orifice— on the surface of the skin, but with the development of the nipple each of the main ducts opens independently on the surface—

It is clear therefore that the nipple is a structure developed in connection with the system of excretory ducts, and it is equally clear that the ducts are not developed until the position & general form of the mammæ have been mapped out in the skin—

I must apologize for the delay in replying to your queries but about the time that I received your letter a great whale came ashore here, and the dissection which I undertook so absorbed my time and thoughts that I fear many matters which should have been attended to were for a time at least forgotten—5

I remain | Yours sincerely | W Turner

## CD annotations

1.1 Kölliker] underl red crayon
1.1 Langer] underl red crayon
3.3 ducts] underl red crayon

## Footnotes

Turner refers to Rudolf Albert von Kölliker and Karl von Langer.
CD cited Turner, on the authority of Kölliker and Langer, on this point in Descent 1: 209.
See Kölliker 1855, pp. 558–61.
CD’s letter to Turner has not been found. The whale was beached near Longniddry on the Firth of Forth, about twelve miles from Edinburgh, on 4 November (see The Times, 6 November 1869, p. 9, 17 November 1869, p. 5).

## Bibliography

Descent: The descent of man, and selection in relation to sex. By Charles Darwin. 2 vols. London: John Murray. 1871.

Kölliker, Rudolf Albert von. 1855. Handbuch der Gewebelehre des Menschen. Für Aerzte und Studirende. 2d edition. Leipzig: Wilhelm Engelmann.

Langer, Karl von. 1852. Über den Bau und die Entwicklung der Milchdrüse bei beiden Geschechtern. Denkschriften der kaiserlichen Akademie der Wissenschaften, Mathematisch-Naturwissenschaftliche Classe 3 (pt 2): 25–38.

## Summary

On the development of the mammae and the glands of the skin. R. A. v. Kölliker and Carl von Langer are the authorities [See Descent 1: 209].

## Letter details

Letter no.
DCP-LETT-7088
From
William Turner
To
Charles Robert Darwin
Sent from
Edinburgh
Source of text
DAR 80: B158–9
Physical description
4pp †