jim nas'tiks, the technical term used to designate any system of exercises specially designed to promote the development of physical and, especially, muscular powers. An excellent gymnastic training is given by baseball, football, rowing and similar amusements, but the special value of formal gymnastic exercises is that they are capable of being scientifically arranged so as to secure not only a general development of muscular power, but also to give suitable training to the separate muscles. Furthermore, they are capable of being applied to each person so as to meet, allow for and, as far as possible, overcome defects in his physical organization. For these purposes an elementary course of gymnastics is of great value to all, especially to the person of sedentary habits. Two general rules may be laid down, which form an efficient guide in self-imposed exercises. The first is the universal rule in mechanics, that the strength of any machine is the strength of its weakest part; the second is the fundamental law of muscular exercise, that it is exercise within the extreme power of a muscle which develops and improves, while straining a muscle weakens and injures it, and excessive exercise develops particular muscles at the expense of the general health. It is quite possible, indeed, to carry general physical exercises too far, and to develop muscular power at the expense of vital strength. Till the age of twelve the ordinary games and pastimes of childhood are generally quite sufficient exercise; after that some very light system of gymnastics may be adopted to aid the development of the system. After the age of thirty-five, unusual muscular efforts are apt to leave persistent strains, and moderate exercise becomes the safest means of developing and giving tone to the muscular system.