{146} SYMPTOMS.--Before entering upon a more accurate and elaborate enumeration of the symptoms of rachitis, I mean to dwell upon peculiar differences which take place according to the age in which the disease makes its appearance. Very young babies--that is, infants of a month or two--develop rachitis in such a manner that many cases are overlooked until it is too late to relieve them in time. This occurrence takes place when there are no prominent causes, such as diarrhoea or other nutritive disorders, nor any premonitory symptoms. Such infants appear to be perfectly well; they have the average weight, and even more; they have plenty of adipose tissue, and look well. The only anomaly appears to be an undue degree of paleness. Without pain or flatulency they are constipated. This constipation is not congenital, as it always is when the colon is unusually long even for an infant, and when the sigmoid flexure is of double or even treble length, but makes its first appearance about the end of the first or the beginning of the second month. It is relieved only when the increasing muscular power of the intestine results in more effective peristalsis. The second symptom is the thoracic groove, to which I shall allude later, and a gradual thickening of the costo-cartilaginous junctures, with or without periosteal pain on pressure. About the same time the cranial softening, craniotabes, with its hyperæmia and perspiration of the entire scalp, and baldness, and the first symptoms of maxillary rachitis, become perceptible. During all this time the epiphysial swellings and the diaphysial curvatures develop but very slowly; but at a very early time chronic bronchial catarrh, with a loose cough, begins to be troublesome. When rachitis begins at a late period--say, about the sixth or eighth month--the aspect of the case is different. The infant has suffered before either from bronchitis and broncho-pneumonia, or in most cases from indigestion and intestinal catarrh. There is some degree of emaciation; the skin does not fit the limbs, as it were--is loose, thin, flabby, and rather dry. The tendency to diarrhoea continues to prevail. The epiphyses, particularly of the lower extremities, are thickened at an early time, curvatures of the tibiæ become apparent, and all the rest of the bones participate in the process, with the exception, sometimes, of those of the head.