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Darwin Correspondence Project

From Valentin Salzmann   18 November 1873

To Mr. Charles Darwin M.A. F.R.S.


In investigating the causes of some of the gestures and actions, the inquiry for which has frequently occupied my thoughts, we find of all the organs of senses—which contribute as is well known so much to the formation of the mimics—the organ of taste to be the moste moveable and the most active. At the same time I found the expression of the emotions which are represented by this organ to be the most comprehensible to me and was therefore the more surprised to find them nowhere explained satisfactorily ⁠⟨⁠    ⁠⟩⁠ own ideas. Harless in his “Plastic Anatomy”1 where he enumerates a great variety of gestures goes so far as to doubt even the ⁠⟨⁠physiogn⁠⟩⁠omical value of the muscles playing about the mouth, although their activity fully agrees with his theory, according to which the different position of the muscles shall excite a sensation upon the skin corresponding to the impression.

I have studied, Sir, your excellent wo⁠⟨⁠rk “⁠⟩⁠On the Expression of the Emotions”, and having found thereby, that you ⁠⟨⁠    ⁠⟩⁠ do not explain the changes which the organs of taste undergo according to their expressing feelings of affection or repulsion, in the manner which I conceive to be the only right one, I feel bound by the interest I take in this matter to communicate to you in a few words my thoughts abo⁠⟨⁠u⁠⟩⁠t it. I may as well presume that any such communication may not be unwelcome to you. A young lady, a friend of mine, will undertake the translating of my letter into English.

An observation similar to that which you have made in cleaning some badly smelling skeleton p. 260. will best explain to you my thoughts.2 If in a sudden fit of hunger we have eaten some bad or tainted meat, we shall for some time loathe to taste the same kind of meat; and if we eat it nevertheless, we believe it to have ever again the same bad taste, nay we think even the bad taste to be in our mouth, as often as we only think of the distasteful morsel; we imagine the saliva to take the taste of it. The consequence of this is, that we unvoluntarily give to to the inside of the mouth a shape which intimates the absence of the sensation of taste: the tongue is kept perfectly free in the middle of the mouth, touching neither the palate nor the gums, the jaws are a little opened, the lips are protruded so that they might touch neither each other, nor the gums, nor the tongue, the cheeks stand off.

These same actions take place not only when thinking of some bad food, but also when thinking of any bad actio⁠⟨⁠n,⁠⟩⁠ any hateful person etc. According to the more or less strong expression of these movements they signify disinclination, contempt, hatred, disgust etc. The highest degree of them is intimated by lolling out the tongue ⁠⟨⁠and⁠⟩⁠ spitting out the saliva.

I therefore consider it more likely that these actions should come from a wish to avoid all sensation of taste rather than from an imitation of vomiting p. 364. or from wanting to show by this sign a wish as if to let an offensive morsel fall out of the mouth p. 258. 261. or that by the raising of the upper lip we should want to close the nostrils p. 2⁠⟨⁠56⁠⟩⁠3 If in connection with this a blowing out of the lips is taking place p. 92. it signifies a simultaneous removal of the bad air from the mouth.

But the mouth will assume an opposite shape if it is affected by some agreeable impression. At the thought of some savoury food, the secretion of saliva is more copious, it makes one’s mouth water, the flow of the gastric juice is stronger, as we may see with dogs that possess a fistula in the stomach. If we think of some sweet meat, the saliva takes an agreeable taste. Having in this instance no reason to avoid the sensation of taste, but on the contrary to seek it, we suck in, we swallow, we give the inside of the mouth a shape so as to excite a full sensation of taste, the tongue lies with the whole of its surface against the roof of the mouth and the gums, the jaws are closed, the lips likewise, the mouth becomes pointed, a so-called sweet mouth, the cheeks are pressed close on the teeth and sometimes form a dimple. With some persons the saliva may be seen trickling down the corners of the mouth. Dogs are licking their beards.

This same expression takes place if we think of some good action or of some beloved person. It is the sign of affection in its different stages till to the most fervent love   The kiss intimates the highest gradation of this expression of the emotions.

Love has therefore indeed a means of expression of its own: it is the gesture of a hungry man at the sight of food. The kiss becomes more a manifestation of the sensation of taste than of touch p. 215. 353. Dogs lick less from a habit originated in the cleansing of their young ones than from a sensation of taste 120. The sucking in of air which we find to be a sign of pleasure in the Greenlander p. 214. forms the antithes⁠⟨⁠is⁠⟩⁠ to the blowing out of badly tasting air and is called forth by the idea of some savoury air.

Sometimes we see the organs of other senses besides those of taste employed in order to express affection, so for instance the sense of smelling with those nations who instead of kissing each other ru⁠⟨⁠b⁠⟩⁠ their noses, or the sense of touch, expressed by the stroking of cats and dogs or by their rubbing against their master.

It is remarkable that there are movements which though performed almost in the same way, may yet express opposite feelings. So I am told that the lolling out of the tongue which we look at as a sign of contempt and scorn, is with the Beduins4 an expression of inclination. During the last war between Germany and France, a great many prisoners of war from Africa passed Esslingen:5 when offered some refreshments, they were seen lolling out the tongue at which gestures people were first offended, until a maid-servant who had spent the great part of her life at Algiers, explained that lolling out the tongue is with Turcos6 etc. a sign of affection. But I doubt not that in this case the tongue will be protruded with the mouth being shut, so that the movement indicates a sensation of taste, whilst we protrude the tongue with our mouth opened so that it intimates the avoiding of all sensation of taste.

The same thing occurs with spitting out. We see this expression generally taking place when a person is dissatisfied with any place or any neighbourhood. The American spits when he is in a comfortable mood, but he spits differently: he spits the saliva out from between his teeth, the jaws being closed; with us, spitting out intimates more an expression of disgust.

Suppressing further remarks on this a⁠⟨⁠nd⁠⟩⁠ divers other points of this interesting subject, in order that I might not importune you, I gladly seize the opportunity of giving you, Sir, the assurance of the high esteem with which I remain | a faithful adherent to your doctrines | Dr. Salzmann

November 18th. 1873. | Esslingen, Wurtemberg, Germany.

CD annotations

1.1 In … English. 2.8] crossed pencil


The reference is to Emil Harless’s Lehrbuch der plastischen anatomie, enthaltend die gesetze für organische bildung und künstlerische darstellung der menschlichen gestalt im allgemeinen und in den einzelnen situationen (Textbook of plastic anatomy, including the organic laws for educational and artistic representation of the human form in general and in individual situations; Harless 1856–8).
In Expression, p. 260, CD discussed how the ‘tendency to retch from a fetid odour’ was ‘immediately strengthened in a curious manner by some degree of habit, though soon lost by longer familiarity with the cause of offence and by voluntary restraint’. He used the example of cleaning the skeleton of a decomposed bird, which caused him to retch; after this, odours of less decomposed birds had the same effect, despite not bothering him before.
In Expression, p. 256, CD discussed the relationship between raising the upper lip and closing the nostrils in response to an offensive odour or in expressing disgust.
Beduin is a variant of Bedouin, the tent-dwelling nomadic peoples of the Arabian, Syrian, Nubian, or Sahara deserts.
The reference is to the Franco-Prussian War (1870–1). Esslingen am Neckar is a city in the Stuttgart region of southern Germany.
A Turco was an Algerian infantryman in the French army.


Expression: The expression of the emotions in man and animals. By Charles Darwin. London: John Murray. 1872.

Harless, Emil. 1856–8. Lehrbuch der plastischen Anatomie, enthaltend die Gesetze für organische Bildung und künstlerische Darstellung der menschlichen Gestalt im Allgemeinen und in den einzelnen Situationen. 3 vols. Stuttgart: Ebner.


Discusses human reactions to pleasant and unpleasant tastes; considers that modifications of these reactions produce several identifiable expressions of general like and dislike.

Letter details

Letter no.
Karl Ludwig Valentin (Valentin) Salzmann
Charles Robert Darwin
Sent from
Source of text
DAR 177: 26
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 9153,” accessed on 21 October 2021,

Also published in The Correspondence of Charles Darwin, vol. 21