Sight—Acuteness of Vision—Chromatic Sensibility—Field of Vision. Visual acuteness is tested by holding letters of a specified size at a certain distance. Sight is generally more acute in criminals than in normal persons; not so, chromatic sensibility, which is tested by giving the patient a number of skeins of different coloured silks, and requesting him to arrange them in series. Persons afflicted with dyschromatopsia confuse the different colours and the different shades of the same colour. Colour-blind people confuse black and red.
Especially important is the examination of the field of vision, as the seat of one of the most serious anomalies discovered by the Modern School, the presence of peripheral scotoma, frequently found in epileptics and born criminals. To test this anomaly, use should be made of Landolt's apparatus ([Fig. 36]). This consists of a semicircular band, which can revolve around a column. The patient rests his chin on a support placed in front of the semicircle in such a manner that the eye under examination is exactly in the centre, and looks directly at the middle point of the semicircle, corresponding to 0 in the scale: the testing object, a small ball, is passed backwards or forwards along the semicircle. A graduated scale, placed on the semicircle, marks the point limiting the field of vision, and the result is registered on a diagram. The average limit of the normal field of vision is 90 mm. on the temporal side, 55 mm. on the nasal side, 55 mm. above and 60 mm. below (see [Fig. 37]). If a suitable instrument is not available, a series of concentric circles may be traced on a slate and the patient placed at a certain distance with one eye covered. The examiner then touches the different points of the circles with his hand and asks the patient whether he can see it when his eye is fixed on the central point. In this way the various points limiting the field of vision are noted and furnish, when united, the boundary line.
Fig. 37
Diagram Showing Normal Vision
Hearing is generally less acute in the criminal than in the normal individual, but does not show special anomalies. It may be tested by speaking in a low voice at a certain distance from the patient, or by holding an ordinary watch a little way from his ear.
Smell. Olfactory acuteness is tested by solutions of essences of varying strength, which the patient should be requested to place in order, indicating the one in which he first detects an odour. Ottolenghi has invented a graduated osmometer which is easy to use. The criminal generally shows olfactory obtuseness.
Taste is tested in the same way as smell, by varying solutions of saccharine or strychnine dropped on to the patient's tongue by means of a special medicine dropper. The mouth should be rinsed out each time. Normal persons taste the bitterness of sulphate of strychnine in a solution 1:600,000; the sweetness of saccharine in a solution 1:100,000. The sense of taste is less acute in criminaloids than in normal persons, and is specially obtuse in born criminals, 33% of whom show complete obtuseness.
Movements. Normal individuals in a state of repose remain almost motionless, and their gestures are always appropriate. Lunatics and imbeciles have a habit of speaking and gesticulating even when they are not interrogated. Nervous diseases manifest themselves in facial contortions or slight spasmodic contractions. In melancholia and all forms of depression, the patient does not gesticulate but remains immovable like a statue with his eyes cast down. Degenerates manifest a fairly varied series of involuntary motions,—twitchings of the muscles, as in chorea, tonic and clonic convulsions and tremors. In senility, chorea, and Parkinson's disease, the tremors are incessant and continue even when the body is in a state of repose; in sclerosis, goitre, and chronic inebriety they accompany voluntary movements, and in this case they are easily detected by making the patient lift the tip of his finger to his nose or a filled glass to his lips. The nearer the hand approaches its goal, the more intense the oscillations become. Above all, the examiner should not fail to ask the patient to put out his tongue. If it protrudes on one side, it is a sign of a serious nervous alteration and nearly always denotes the beginning or remains of paralysis, or partial apoplectic strokes.
Muscular Strength is measured by a common dynamometer ([Fig. 38]), which the patient is requested to grasp with all his might. Compressive strength is tested by compressing the oval. In order to test tractive strength, the dynamometer is fastened to a nail at the point C, and the patient pulls with all his strength at D. The effort is registered on a graduated scale and is of importance for detecting left-handedness and measuring the extraordinary force that is displayed in certain states of excitement.