There are, as every man and woman ought to know, two main and quite distinct diseases (any other being unimportant) poetically termed "Venereal" because chiefly, though not by any means only, propagated in the intercourse over which the Roman goddess Venus once presided. These two diseases are syphilis and gonorrhoea. Both these diseases are very serious, often terrible, in their effects on the individual attacked, and both liable to be poisonous to the race. There has long been a popular notion that, while syphilis is indeed an awful disease, gonorrhoea may be accepted with a light heart. That, we now know, is a grave mistake. Gonorrhoea may seem trivial at the outset, but its results, especially for a woman and her children (when it allows her to have any), are anything but trivial; while its greater frequency, and the indifference with which it is regarded, still further increase its dangers. About the serious nature of syphilis there is no doubt. It is a comparatively modern disease, not clearly known in Europe before the discovery of America at the end of the fifteenth century, and by some authorities[2] to-day supposed to have been imported from America. But it soon ravaged the whole of our world, and has continued to do so ever since. During recent years it has perhaps shown a slight tendency to decrease, though nothing to what could be achieved by systematic methods; but its evils are still sufficiently alarming. Exactly how common it is cannot be ascertained with certainty. At least 10 per cent., probably more, of the population in our large cities have been infected by syphilis, some before birth. In 1912 for an average strength of 120,000 men in the English Navy, nearly 300,000 days were lost as a result of venereal disease, while among 100,000 soldiers in the Home Army for the same year, an average of nearly 600 men were constantly sick from the same cause. We may estimate from this small example how vast must be the total loss of working power due to venereal disease. Moreover, in Sir William Osler's words, "of the killing diseases syphilis comes third or fourth." Its prevalence varies in different regions and different social classes. The mortality rate from syphilis for males above fifteen is highest for unskilled labour, then for the group intermediate between unskilled and skilled labour, then for the upper and middle class, followed by the group intermediate between this class and skilled labour, while skilled labour, textile workers, and miners follow, and agricultural labourers come out most favourably of all. These differences do not represent any ascending grade in virtue or sexual abstinence, but are dependent upon differences in social condition; thus syphilis is comparatively rare among agricultural labourers because they associate only with women they know and are not exposed to the temptation of strange women, while it is high among the upper class because they are shut out from sexual intimacy with women of