The wage-earning opportunities of women in the three great groups of occupations, domestic service, manufacturing industries, and trade and transportation, have also changed decidedly. Thousands, of course, have always been employed in domestic service, which has acted as the complement of the industrial pursuits. The opportunity to “hire out” has continually confronted the working woman and frequently, when she complained that her conditions of work were hard and her pay inadequate, she has been admonished by philanthropists and even by economists to betake herself to the kitchen, whose homelike conditions, high wages and pressing need of her labor have always been loudly proclaimed. The conditions and problems of domestic service, indeed, have changed far less than those of any other occupation. Nevertheless, the proportion of all gainfully employed women engaged in domestic and personal service has steadily decreased.[2] In the manufacturing industries, on the other hand, great changes have taken place. The entrance of women into these industries may be attributed to three principal causes, machinery, artificial power and division of labor. All of these are in part the cause and in part the effect of an unprecedented development of wholesale, as opposed to retail production, and this growth of wholesale trade is itself primarily the result of improved means of communication and transportation. These three factors have also caused a considerable amount of shifting of occupations. Under the domestic system of labor woman’s work and man’s work were clearly defined, women doing the spinning, part of the weaving, the knitting, the sewing and generally the cooking. But with the introduction of machinery for spinning and weaving thousands of hand workers were thrown out of employment. It is not surprising to learn that the first spinners and weavers by machinery were women. Later, however, mule spindles, operated by men, were introduced for part of the work. In certain other cases, too, machinery has caused the substitution of men for women in industries formerly considered as belonging to woman’s sphere. Women’s suits, for instance, are now largely made by men tailors, and men dressmakers and milliners are not uncommon. Men bake our bread and brew our ale and wash our clothes in the steam laundry. At present men even clean our houses by the vacuum process.