6. The removal of children into the country before the approach of warm weather. This advice is peculiarly necessary during the whole period of dentition. I have never known but one instance of a child being affected by this disease, who had been carried into the country in order to avoid it. I have only to add to the above observations, that since the prevalence of the yellow fever in Philadelphia after the year 1793, the cholera infantum has assumed symptoms of such malignity, as to require bleeding to cure it. In some cases, two and three bleedings were necessary for that purpose. OBSERVATIONS ON THE _CYNANCHE TRACHEALIS_. The vulgar name of this disease in Pennsylvania is HIVES. It is a corruption of the word _heaves_, which took its rise from the manner in which the lungs heave in breathing. The worst degree of the disease is called the BOWEL HIVES, from the great motion of the abdominal muscles in respiration. It has been called suffocatio stridula by Dr. Home, and cynanche trachealis by Dr. Cullen. Professor Frank calls it trachitis, and Dr. Darwin considers it as a pleurisy of the windpipe. By the two latter names, the authors mean to convey the correct idea, that the disease is the same in its nature with the common diseases of other internal parts of the body. It is brought on by the same causes which induce fever, particularly by cold. I have seen it accompany, as well as succeed, the small-pox, measles, scarlet-fever, and apthous sore throat. In the late Dr. Foulke it succeeded acute rheumatism. The late Dr. Sayre informed me, he had seen it occur in a case of yellow fever, in the year 1798. It sometimes comes on suddenly, but it more frequently creeps on in the form of a common cold. Its symptoms are sometimes constant, but they more generally remit, particularly during the day. It attacks children of all ages, from three months to five years old. But it occasionally attacks adults. It generally runs its course in three or four days, but we now and then see it protracted in a chronic and feeble form, for eight and ten days.