From the material point of view (to quote Séglas again), the predominant symptom is the eructation, and the object in determining the accessory symptoms is to distinguish it from gastric eructations properly so called, the consequence of improper fermentation. In our case the appetite is good, and the digestion normal--tympanites, splashing, and abdominal pain are all absent. The gases evolved are inodorous, and their analysis in different cases (Ponagen, Hoppe-Seyler, Pitres, Sabrazès and Rivière) has shown that so far from containing any abnormal constituent, they have almost the same composition as atmospheric air. Application of the ear to the vertebral column at the level of the stomach enables one to detect a noise that appears to correspond to the passage of air into that viscus, and less than a second later comes the eructation. Facts of another kind indicate the participation of a psychical element. The activity of the tic increases under the influence of the emotions and decreases or disappears momentarily at the bidding of the will. Distraction, concentration of the attention on some particular thing, speaking, reading aloud, are also calculated to suspend its manifestations. In some cases, especially where there is an association with hysteria, support is given to the theory of its psychical origin by the observation that prolonged opening of the mouth, and the administration of mica panis pills or of distilled water tinted with methylene blue, have had a definite effect in controlling the spasm (Pitres). Moreover, the co-existence or pre-existence of intellectual troubles or mental peculiarities is often incontrovertibly proved by a painstaking psychological examination. In reality this aerophagic tic is a symptom-complex encountered in very different pathological conditions. No doubt its frequency is greatest and its development highest in hysteria, but we are in error if we suppose that it is the exclusive appurtenance of that disease: its occurrence in our case of general paralysis is evidence to the contrary. I have noted it where there was not the slightest suspicion of hysterical antecedents. Nevertheless its relation to pathological mental states of some form or another is invariable. It is often found in cases of insanity of the obsessional or of some other type.