The severe changes of temperature are not without their influence on this sensitive membrane. If these changes are sudden, as for example in our northern states where the temperature will vary from 50° to 70° Fah., in a single day, the danger of injury becomes imminent, and the lungs require to be strong indeed to resist their effects. Sudden transition from the hot close atmosphere of the barn or stable to the chilling winds of winter is equally hurtful. But it is not alone the transition from warmth to cold that is injurious. The general relaxation attendant on the sudden change from a cold bracing atmosphere to one unduly hot is even more injurious. How frequently do human beings suffer from colds as the result of a close sultry period at once supervening on a clear cold one? How extensively do chest diseases prevail among horses brought from the clear pure atmosphere of the field, and shut up in close, hot stables? Here, no doubt, there is superadded the impurity of the too often infected air, the change of diet, of exercise and of general care yet we find that affections of the air passages are to a great extent in ratio with the heat of the building. Hence their constant presence in dealer’s stables where it is thought desirable to keep the horses warm to hasten the improvement in the coat. The suddenness of the transition is usually a principal cause of injury. Where the climate changes slowly the animal economy becomes habituated to it and resists successfully the injurious influences. Thus when spring merges gradually into summer and autumn into winter, diseases of this kind are far less frequent. But on the other hand a sudden and extreme variation of temperature, whether in the ordinary course of the season or from a wide change of latitude, is notoriously attended with diseases of the air passages. Ayrshire, shorthorn and Jersey cattle, when first imported into the Northern States of America, contract colds, consumption and other chest diseases to a far greater extent than the native races, though their progeny or even they themselves after acclimatization, exhibit powers of resistance nearly equal to the native stock. Sheep that have been shorn in midwinter or early spring often repay the inhumanity of their owners by dying of inflamed lungs. Southdown and Leicester sheep, sent from England to the north of Scotland, demand at first the greatest care to protect them against the increased rigor of the climate. The army veterinary statistics of France show that horses transported from the southern parts of the country to the more northern stations, suffer largely from pulmonary affections. But if the change is effected slowly the requisite powers of resistance are acquired and the novel conditions of life cease to be injurious. That this varied power of resistance is not confined to the higher animals would appear from the experiments of W. Edwards on cold blooded animals. He subjected them in winter and in summer respectively to a