There are other symptoms that point to carbonic acid poisoning, which it will be interesting to review. A great majority of these symptoms are to be found in every case of chlorosis. The muscles become weak at first, because their nutrition is interfered with, and they waste away, and secondly they become irritable from the poisonous presence of the carbonic acid, and so are often very painful. The patients are easily tired out; some, indeed, feel tired all the time, getting up in the morning as worn out as when they retired at night. The nervous system suffers as much, because the principal nerve food is oxygen, and if there is no blood, there can be no oxygen; a starved nerve is a painful nerve. We find neuralgias, affecting the different parts of the body, the rule; when these are located in the external muscles, they are easily recognized, but when located in the deep organs, as the ovaries or the womb, they are generally mistaken for something else. The nerves of these individuals being in such an irritable state, it is natural to infer, that hysteria is often to be found as one of the complications, so that habitual sadness, and abnormal longings after chalk, lead pencils, and other indigestible articles are prominent symptoms. The circulatory system suffers derangements that are characteristic of chlorosis. Palpitation of the heart is a prominent symptom; this is partly due to the irritation of the carbonic acid on the cardiac nerves, and partly to sensitiveness of the patient, owing to a morbidly-increased sensibility of the whole body. Chlorotic patients blush up at times, only to be followed by a green paleness that is peculiar to the disease. Pain in the region of the heart, and disturbances of the digestion, are sometimes prominent symptoms. There is no feeling of hunger; eating is not so much from hunger, but more from a sense of duty to keep up the strength. A heavy or full feeling is often experienced after a meal, and a sourish eructation will give relief to the oppression, because the walls of the stomach are relaxed and in sympathy with the general debility. But in all cases of chlorosis the sexual functions are the seat of the greatest disturbance; amenorrhœa or the suppression of the menses is the most prominent symptom. The ovaries no longer seem to expel ripened ova, for there are no indications that point to their activity, because there is not only an absence of the show, but also an absence of the other signs that were noted when we considered menstruation and ovulation. There are a great many other diseases of which amenorrhœa is a prominent symptom; these will be referred to when separate diseases become the subject of special inquiry.