urselves in possession of enough material for our purpose to make it possible to carry our studies further。 The study of this book of Darwin's I believe absolutely necessary to each criminalistfor he meets in every direction； expositions and explanations that are related to cases he has already experienced in practice or is sure to experience。 I present here only a few of Darwin's most important notes and observations in order to demonstrate their utility for our purpose。
As subjects for study he recommends children because they permit forms of expression to appear vigorously and without constraint； lunatics； because they are subject to strong passions without control； galvanized persons； in order to facilitate the muscles involved； and finally； to establish the identity of expression among all races of men and beasts。 Of these objects only children are important for our purpose。 The others either are far removed from our sphere of activity； or have only theoretic value。 I should； however； like to add to the subjects of observation another； viz。； the simple unstudied persons； peasants and such otherwise unspoiled individuals whom we may believe innocent of all intention to play a comedy with us。 We can learn much from such people and from children。 And it is to be believed that in studying them we are studying not a special class but are establishing a generally valid paradigm of the whole of mankind。 Children have the same features as adults only clearer and simpler。 For； suppose we consider any one of Darwin's dicta；e。 g。； that in the expression of anger and indignation the eyes shine； respiration becomes more rapid and intense； the nostrils are somewhat raised； the look misses the opponent； these so intensely characteristic indices occur equally in the child and the adult。 Neither shows more or fewer； and once we have defined them in the child we have done it for the adult also。 Once the physiognomy of children and simple people has been studied；
＇1＇ L。 P。 Gratiolet： De la Physiognomie et des Mouvements d'Expression。 Paris 1865。
the further study of different kinds of people is no longer difficult； there is only the intentional and customary masking of expression to look out for； for the rest； the already acquired principles； mutandis mutatis； are to be used。
Darwin posits three general principles on which most expressions and gestures are to be explained。 They are briefly：
I。 The principle of purposeful associated habits。
II。 The principle of contradication。
III。 The principle of the direct activity of the nervous system。
With regard to the first。 When； in the course of a long series of generations； any desire； experience； or disinclination； etc。； has led to some voluntary action； then； as often as the same or any analogous associated experience is undergone； there will arise a tendency to the realization of a similar action。 This action may no longer have any use but is inherited and generally becomes a mere reflex。
This becomes clearer when one notices how often habit facilitates very complex action：the habits of animals； the high steps of horses； the pointing of pointers； the sucking of calves； etc。 It is difficult for us in falling to make opposite movements to stretching out the arms； even in bed； we draw on our gloves unconsciously。 Gratiolet says： ‘‘Whoever energetically denies some point； etc。； shuts his eyes； if he assents he nods and opens his eyes wide。 Whoever describes a terrible thing shuts his eyes and shakes his head； whoever looks closely raises his eye…brows。 In the attempt to think the same thing is done or the eye…brows are contracted both make the glance keener。 Thence follows the reflex activity。''
With regard to the second。 Dogs who are quarrelling with cats assume the appearance of battleif they are kindly…minded they do the opposite； although this serves no purpose。 M。 Taylor＇1＇ says； that the gesture language of the Cistercians depends considerably on antithesis； e。 g。； shrugging the shoulders is the opposite of firmness； immovability。
With regard to the direct activity of the nervous system； examples are paling； trembling （fear； terror； pain； cold； fever； horror； joy）； palpitation of the heart； blushing； perspiring； exertion of strength； tears； pulling the hair； urinating； etc。 With these subdivisions it will be possible to find some thoroughfare and to classify every phenomenon。
We want to discuss a few more particulars in the light of Darwin's
＇1＇ Taylor： Early History of Mankind。
examples。 He warns us； first of all； against seeing＇1＇ certain muscle movements as the result of emotional excitement； because they were looked for。 There are countless habits； especially among the movements of the features； which happen accidentally or as the result of some passing pain and which have no significance。 Such movements are often of the greatest clearness； and do not permit the unexperienced observer to doubt that they have important meanings； although they have no relation whatever to any emotional condition。 Even if it is agreed only to depend on changes of the whole face； already established as having a definite meaning； there is still danger of making mistakes； because well accredited facial conditions may occur in another way （as matters of habit； nervous disturbances； wounds； etc。）。 Hence in this matter； too； care and attention are required； for if we make use of any one of the Darwinian norms； as； for example； that the eyes are closed when we do not want to see a thing or when we dislike it； we still must grant that there are people to whom it has become habitual to close their eyes under other and even opposed conditions。
We must grant that； with the exception of such cases； the phenomena are significant during examinations； as when we show the accused a very effective piece of evidence； （e。 g。： a comparison of hand…writings which is evidential；） and he closes his eyes。 The act is then characteristic and of importance； particularly when his words are intended to contest the meaning of the object in question。 The contradiction between the movement of his eyes and his words is then suggestive enough。 The same occurs when the accused is shown the various possibilities that lie before himthe movement of the examination； the correlations and consequences。 If he finds them dangerous； he closes his eyes。 So with witnesses also； when one of them； e。 g。； deposes to more； and more harmfully； than according to our own notion he can explain； he will close his eyes； though perhaps for an instant only； if the inevitable consequences of his deposition are expounded to him。 If he closes his eyes he has probably said too much； and the proper moment must not be missed to appeal to his conscience and to prevent more exaggerated and irresponsible assertions。
This form of closing the eyes is not to be confused with the performances of persons who want to understand the importance of their depositions and to collect their senses； or who desire to review
＇1＇ J。 Reid： The Muscular Sense。 Journal of Mental Science； XLVII； 510。
the story mentally and consider its certainty。 These two forms of closing the eyes are different： the first； which wants to shut out the consequences of testimony； is much shorter； the latter longer； because it requires a good deal of time to collect one's senses and to consider a problem。 The first； moreover； is accompanied by a perceivable expression of fear； while the latter is manifest only by its duration； what is most important is a characteristic contemporary and perceivable defensive movement of the hand； and this occurs only in the cases where the desire is to exclude。 This movement occurs even among very phlegmatic persons； and hence is comparatively reliable； it is not made by people who want undisturbedly to study a question and to that end shut their eyes。
In a similar way there is significance in the sudden closing of the mouth by either the accused or the witness。 Resolution and the shutting of the mouth are inseparable； it is as impossible to imagine a vacillating； doubting person with lips closely pressed together； as a firm and resolute person with open mouth。 The reason implies Darwin's first law： that of purposeful associated habits。 When a man firmly resolves upon some deed the resolution begins immediately to express itself in movements which are closely dependent upon bodily actions。 Even when I suddenly resolve to face some correctly… supposed disagreeable matter； or to think about some joyless thing； a bodily movement； and indeed quite an energetic one； will ensue upon the resolutionI may push my chair back； raise my elbows； perhaps put my head quickly between my hands； push the chair back again； and then begin to look or to think。 Such actions； however； require comparatively little bodily exertion； much more follows on different types of resolutionsin short； a firm resolution requires a series of movements immediately to follow its being made。 And if we are to move the muscles must be contracted。 And it is； of course； obvious that only those muscles can be set in action which are； according to the immediate situation of the body； free to move。 If we are sitting down； for example； we can not easily make our feet conform to the movement of a march forward； nor can we do much with the thighs； hence the only muscles we can use are those of the face and of the upper limbs。 So then； the mouth is closed because its muscles are contracted； and with equal significance the arms are thrust outward sharply； the fist clenched； and the fore…arm bent。 Anybody may try the experiment for himself by going through the actions enumerated and seeing whether he does not become filled with a sense of resolution。 It is to be especially observed； as has already been indicated； that not only are mental states succeeded by external movements； but imitated external movements of any kind awaken； or at least plainly suggest； their correlated mental states。
If； then； we observe in any person before us the signs of resolution we may certainly suppose that they indicate a turn in what he has said and what he is going to say。 If they be observed in the accused； then he has certainly resolved to pass from denial to confession； or to sti