The critical period when the first sexual offense of these women was committed appears to belong between the 14th and 21st years of life; the average of 1,106 such girls is 17 years. Twenty-five servants first erred between the 9th and 26th years; their average age was 16; 40 factory workers, first erring between 14 and 22, averaged a little over 17; 110 salesgirls give the same result. Occasionally they declare that they never knew the time when they were virtuous. "When I was a kid of 6, I used to kiss sailors and other men for candy and do other things," said one. Naturally the age is highest in case of the former teachers, of whom one reports her first offense at 21, another at 20; one or two report their fall in their 18th year. The average time which elapsed before the girls finally drifted into professional prostitution was two years, _i. e._, when they were 19 years of age. The life of the professional prostitute has been estimated at five years, on the ground that she dies, withdraws, or is incapacitated after she has been in the business on the average for that length of time. But a study of more than a thousand prostitutes, all now actively engaged in the business in New York City, does not sustain this view. The majority of these girls, though entering the life before 18, are at 24 still active and aggressive in seeking trade. There is a sudden drop, however, at 25, fluctuating more or less until the age of 30 is reached. Of the 1,097 professional women whose histories were carefully compiled on this point, 15 were exceedingly active at 32, 13 at 34, 11 at 40, 3 at 44, and 3 at 50. The average age of the 1,097 who are at present inmates of vice resorts, solicitors in saloons, and on the streets, is 25 years. It is curious to note that prostitution is definitely stratified. Women divide themselves into three distinct classes and recognize the subdivisions. To the upper class belong the inmates of $5 and $10 houses. The middle class is formed by girls in one dollar and fifty cent establishments. The street girls are, generally speaking, at the bottom. As in the upper, so in the underworld, social status changes with prosperity or adversity, though the tendency--by reason of the progressive demoralization of the life--is definitely downwards. Under the influence of age, dissipation and disease, physical deterioration rapidly sets in. Those who are at the top fall into the lower classes, except in the cases in which they become madames, managers or mistresses, or abandon the life. Those in the middle class usually end on the streets. (b) THE CUSTOMER