It is improbable that any single community has ever presented so composite a picture of human traits in such bold relief as appeared in the City of Halifax upon the day of the explosion. Human phenomena which many knew of only as hidden away in books, stood out so clearly that he who ran might read. Besides the physiological reactions there was abundant illustration of hallucination, delusion, primitive instincts, and crowd psychology as well of other phenomena all of which have important sociological significance tending either to prolong disintegration, or to hasten social recovery. The first of these phenomena was the "stun" of the catastrophe itself. The shock reaction at Halifax has been variously described. It has been graphically likened "to being suddenly stricken with blindness and paralysis." It was a sensation of utter helplessness and disability. "We died a thousand horrible deaths" ran one description, "the nervous shock and terror were as hard to bear as were the wounds." "The people are dazed," wrote another observer, "they have almost ceased to exercise the sensation of pain." This physiological reaction animals and men shared alike. The appearance of the terror-stricken horses was as of beasts which had suddenly gone mad. A physiological accompaniment of shock and distraction is the abnormal action of the glands. The disturbance of the sympathetic nervous system produced by the emotional stress and strain of a great excitement or a great disappointment is reflected in the stimulation or inhibition of glandular action. Much physical as well as nervous illness was precipitated by the grief, excitement and exposure of the disaster.[39] Among cases observed were those of diabetes, tuberculosis and hyper-thyroidism, as well as the nervous instability to which reference is subsequently made. Such an epidemic of hyper-thyroidism--exaggerated action of the thyroid gland--is said to have followed the Kishineff massacres, the San Francisco earthquake and the air-raids on London.[40] As to diabetes, it has been shown that emotions cause increased output of glycogen. Glycogen is a step toward diabetes and therefore this disease is prone to appear in persons under emotional strain ... so common is this particular result in persons under prolonged emotion that someone has said that "when stocks go down in New York, diabetes goes up."[41] [39] For a full discussion of nervous disorders induced by an explosion at short range, _vide_ Roussy and Llermette, _The Psychoneuroses of War_ (London, 1918), ch. x. [40] Brown, W. Langden, Presidential address to Hunterian Society, London. [41] Crile, George W., _The Origin and Nature of the Emotions_ (Phila., 1915), p. 163. Turning now to other psychological aspects, we have to note the presence of hallucination in disaster.