man is given materials, and required to make bread. The results will have some anthropological value; it is of interest to know that this or that way will be so and so often followed. From the baker's point of view, on the other hand, they will possess but little worth. Now it is one of the commonest errors, that since we are all using our minds, in some way or another, everyone is qualified to take part in psychological experimentation. As well maintain, that because we all eat bread, we are all qualified to bake it.
The position will not be granted, at first sight. It will be objected that the end of the experiment is, after all, the justification of its name, – for we receive untrained students into our university laboratories, and all agree in calling their work psychological. It is, unfortunately, true that an adequate preparation for experimental investigation is very rare among those who enter the psychological laboratory. But, of course, the fact of entering does not make them psychologists; training is needed, as it is in Physiology or in any other science. And the whole objection really supports the argument. If the end of the psychological experiment be Psychology, then assuredly such a laboratory as that outlined above is not psychological; for its chief end is not knowledge of mental process, but statistics relating to "human faculty."
To resume, then. The psychological experiment presupposes, almost universally, practice; – practice in introspection, practice in attentional concentration, practice in the control of the particular apparatus employed. The anthropometrical experiment requires at most only so much practice as is necessary for the correct carrying out of instructions. The value of the former is – or should be – as much qualitative (for analysis and description) as quantitative; the value of the latter is solely quantitative. The similarity of the methods employed by the two sciences ceases to be misleading, when we remember the relation of these to one another. As is social psychology to anthropology, so is individual psychology to anthropometry.
We have been dealing with those experiments which are common, in name at least, to the psychological and anthro-
