In the spring, we have still the same diseases prevalent, and in addition, measles, scarlet fever, small-pox, and chicken pox, which increase in liability towards the close of this season, and with the first weeks of summer. In the summer, disease is less prevalent than at any other period of the year; but towards its middle and close, and through the whole of the autumnal months, bowel complaints may be expected, in the forms of diarrhoea, cholera, and dysentery. 2. THE INFLUENCE OF A HEREDITARY PREDISPOSITION TO CERTAIN DISEASES.-- Without entering into this subject at large, still it may be useful to remark, that in some families there is a predisposition to some diseases, which, occurring in the first child, will, as each succeeding child is born, attack at the same age. Amongst other diseases of this class are, croup, hooping-cough, and water in the head. This observation should not only lead a mother to be alive to the possibility of the successional occurrence of these diseases in her family, and so early note their appearance, and seek medical advice, but should at the same time make her most anxious, on the one hand, to shield her child from all their exciting causes, and on the other, to adopt those measures which may contribute indirectly to overcome the constitutional predisposition to them. Of the scrofulous constitution, I will merely mention here, that it is of the greatest importance, where a predisposition to this disease exists in a family, that a mother should immediately attend to any alteration in the gait or contour of her child, and give prompt attention also to any complaint made of swelling about a joint, although it may be unattended with pain. The importance of this remark will be seen by contrasting the result of the following cases which occurred in children of the same family. Case I. A. B., a female child, having blue eyes, light hair, and a fair complexion, in the early part of the year 1838, being then two years of age, had an enlargement of the left knee joint. For some weeks previous to this time, there had been a degree of heat about the part; but as no pain apparently existed, it was not regarded as of any consequence, and nothing was done. The child, living in the neighbourhood of London, was afterwards placed under medical treatment. Two or three months having elapsed, it was brought to town, and shown to me, in consequence of a slight tumefaction over the lower part of the spine. This soon disappeared under the measures employed, and eventually the disease of the knee (evidently scrofulous) was arrested, so that now the case promises to be cured; but the joint will for ever be stiff, and the limb thus affected shorter than the other. Case II. G. B., the brother of the above, a handsome boy, with light hair, fine blue eyes,--indeed, very much like his little sister,--in the year 1836, had enlargements of the glands in his neck, which were relieved by the treatment resorted to.