cannot be too lightly dismissed, when he rates the percentage of syphilitics in clerks and merchants in Berlin between the ages of 18 and 28 as 45 per cent. Pinkus estimated that one man in five in Germany has had syphilis. Recently published data by Vedder, covering the condition of recruits drawn to the army from country and city populations, estimate 20 per cent syphilitics among young men who apply for enlistment, and 5 per cent among the type of young men who enter West Point and our colleges. It can be pointed out also with justice that the percentage of syphilis in any class grouped by age increases with the age, since so few of the cases are cured, and the number is simply added to up to a certain point as time elapses. Even the army, which represents in many ways a filtered group of men, passing a rigorous examination, and protected by an elaborate system of preventions which probably keeps the infection rate below that of the civil population, is conceded by careful observers (Nichols and others) to show from 5 to 7 per cent syphilitics. Attention should be called to the difference between the percentage of syphilis in a population and the percentage of venereal disease. The inclusion of gonorrhea with syphilis increases the percentages enormously, since it is not infrequently estimated that as high as 70 per cent of adult males have gonorrhea at least once in a lifetime.

On the whole, then, it is conservative to estimate that one man in ten has syphilis. Taking men and women together on the basis of one of the latter to five of the former, and excluding those under fifteen years of age from consideration, this country, with a population of 91,972,266,[5] should be able to muster a very considerable army of 3,842,526, whose influence can give a little appreciated but very undesirable degree of hyphenation to our American public health. In taking stock of ourselves for the future, and in all movements for national solidarity, efficiency, and defense, we must reckon this force of syphilo-Americans among our debits.

The Primary Stage of Syphilis

The So-called Stages of Syphilis.—The division of the course of syphilis into definite stages is an older and more arbitrary conception than the one now developing, and was based on outward signs of the disease rather than on a real understanding of what goes on in the body during these periods. The primary stage was supposed to extend from the appearance of the first sore or chancre to the time when an eruption appeared over the whole body. Since the discovery of the Spirochæta pallida, the germ of the disease, our knowledge of what the germ does in the body, where it goes, and what influence it has upon the infected individual, has rapidly extended. We now appreciate much more fully than formerly that at the very beginning of the disease there is a time when it is almost purely local, confined to the first sore itself, and perhaps to the glands or kernels in its immediate neighborhood. Thorough and prompt treatment with the new and powerful aid of salvarsan ("606") at this stage of the disease can kill all the germs and prevent the disease from getting a foothold in the body which only years of treatment subsequently can break. This is the critical moment of syphilis for the individual and for society, and its importance and the value of treatment at this time cannot be too widely understood.

Peculiarities of the Germ.—Many interesting facts about the Spirochæta pallida explain peculiarities in the disease of which it is the cause. Many germs can be grown artificially, some in the presence of air, others only when air is removed. The germ of syphilis belongs in the latter class. The germ that causes tuberculosis, a rod-like organism or bacillus, can stand drying without losing its power to produce the disease, and has a very appreciable ability to resist antiseptic agents. If the germ of syphilis were equally hard to kill, syphilis would be an almost universal disease. Fortunately it dies at once on drying, and is easily destroyed by the weaker antiseptics provided it has not gained a foothold on favorable ground. Its inability to live long in the presence of air confines the source of infection largely to those parts of the body which are moist and protected, and especially to secretions and discharges which contain it. Its contagiousness is, therefore, more readily controlled than that of tuberculosis. It is impossible for a syphilitic to leave a room or a house infected for the next occupants, and it is not necessary to do more than disinfect objects that come in contact with open lesions or their secretions, to prevent its spread by indirect means. Such details will be considered more fully under the transmission and hygiene of the disease.

Mode of Entry of the Germ.—The germ of the disease probably gains entrance to the body through a break or abrasion in the skin or the moist red mucous surfaces of the body, such as those which line the mouth and the genital tract. The break in the surface need not be visible as a chafe or scratch, but may be microscopic in size, so that the first sore seems to develop on what is, to all appearances, healthy surface. It should not be forgotten that this surface need not be confined to the genital organs, since syphilis may and often does begin at any part of the body where the germ finds favorable conditions for growth.

Incubation or Quiescent Period.—Almost all germ diseases have what is called a period of incubation, in which the germ, after it has gained entrance to the body, multiplies with varying rapidity until the conditions are such that the body begins to show signs of the injury which their presence is causing. The germ of syphilis is no exception to this rule. Its entry into the body is followed by a period in which there is no external sign of its presence to warn the infected person of what is coming. This period of quiescence between the moment of infection with syphilis and the appearance of the first signs of the disease in the form of the chancre may vary from a week to six weeks or even two months or more, with an average of about two or three weeks.

In the length of the incubation period and the comparatively trifling character of the early signs, the germ of syphilis betrays one of its most dangerous characteristics. The germ of pneumonia, for example, may be present on the surface of the body, in the mouth or elsewhere, for a long time, but the moment it gets a real foothold, there is an immediate and severe reaction, the body puts up a fight, and in ten days or so has either lost or won. The germ of syphilis, on the other hand, secures its place in the body without exciting very strenuous or wide-spread opposition. The body does not come to its own defense so well as with a more active enemy. The fitness of the germ of syphilis for long-continued life in the body, and the difficulty of marshaling a sufficient defense against it, is what makes it impossible to cure the disease by any short and easy method.

The First Sore or Chancre.—The primary lesion, first sore or chancre,