Stammering. This defect of speech is characterised by lack of co-ordination in the muscular movements of inspiration or expiration, or in those of the glottis or of the lips and tongue. The complex series of ordered muscular movements concerned in the production of speech is, in the person who stammers, deranged and thrown out of gear by the involvement of one or other of the muscles in a condition of spasm. Stammering is usually first met with in early childhood. It often becomes worse up to the period of puberty, and then frequently improves. Nine-tenths of the sufferers are males. It is sometimes hereditary, and is occasionally met with in persons who belong to families with a history of nervous disorders. Something can be done to remedy the condition by insisting on slow and deliberate speech. In some cases considerable improvement has resulted from the practice of intoning in speaking. In many cases, however, although improvement may occur, it is impossible to effect an absolute cure.