=Diarrh[oe]a.=--I have, therefore, comparatively little to say about _diarrh[oe]a_ in children, important though it is, for its symptoms force themselves on the notice even of the least observant. There are, however, a few points concerning it worth bearing in mind. Before the commencement of teething, diarrh[oe]a is almost always the result of premature weaning, or of a diet in some respect or other unsuitable. As soon as teething begins, the liability to diarrh[oe]a increases greatly, and cases of it are more than twice as frequent, and twice as fatal, between the ages of six and eighteen months as they were in the first six months of life; while, as soon as teething is over, their number immediately declines again to the half of what it was during the continuance of that process. The practical conclusions to be drawn from these facts are that looseness of the bowels during teething is not a desirable occurrence to be promoted, as some mistakenly imagine, but a risk to be by all means avoided, and I may add, when it does take place, far less easy to control than constipation is to remedy. And next, that in order to prevent its occurrence, care should be taken to make changes in the diet of a child, not during the time when a fresh eruption of teeth is taking place, but during one of the pauses in that process. There are certain seasons of the year when diarrh[oe]a is specially prevalent, independent of any change in diet, or alteration, in any respect, of the circumstances in which the child is placed. Thus, in May, June, and July, diarrh[oe]a is twice as prevalent among children at all ages as in November, December, and January; and in August, September, and October, its prevalence is three times as great as during the winter months. The high mortality of children in the summer months is due almost entirely to diarrh[oe]a, and even the bitter Northern winter of a city like Berlin is a third less fatal to infants and young children than the heat of its short summer. The next point to remember is that mere looseness of the bowels is never to be regarded during the first three years of life as of no importance; for I have seen infants die exhausted from its continuance, even though the examination of the body after death showed almost no sign of disease. Doctors distinguish two forms of diarrh[oe]a: the simple, or, as it is technically called, catarrhal diarrh[oe]a; and inflammatory diarrh[oe]a, or dysentery. The one may pass into the other, just as a common cold, or catarrh, may pass, if unattended to, into a dangerous bronchitis.