It is also a well ascertained fact that effectual old age will be brought on at an earlier period by overwork; overwork shortens the working life-time of the workman.

Thorough speeding-up ("Scientific Management" ?) will unduly shorten this working life-time, and so it may, somewhat readily, result in an uneconomical consumption of the community's man-power, by consuming the workmen at a higher rate of speed, a higher pressure, with a more rapid rate of deterioration, than would give the largest net output of product per unit of man-power available, or per unit of cost of production of such man-power.
On this head the guiding incentives of the businessman and the material interest of the community at large--not to speak of the selfish interest of the individual workman--are systematically at variance.

The cost of production of workmen does not fall on the business concern which employs them, at least not in such definite fashion as to make it appear that the given business concern or businessman has a material interest in the economical consumption of the man-power embodied in this given body of employees.

Some slight and exceptional qualification of this statement is to be noted, in those cases where the processes in use are such as to require special training, not to be had except by a working habituation to these processes in the particular industrial plant in question.

So far as such special training, to be had only as employees of the given concern, is a necessary part of the workman's equipment for this particular work, so far the given employer bears a share and an interest in the cost of production of the workmen employed; and so far, therefore, the employer has also a pecuniary interest in the economical use of his employees; which usually shows itself in the way of some special precautions being taken to prevent the departure of these workmen so long as there is a clear pecuniary loss involved in replacing them with men who have not yet had the special training required.
Evidently this qualifying consideration covers no great proportion of the aggregate man-power consumed in industrial enterprises under business management.