The next duty was to review the needs of the race. The tasks and abilities of every family were measured, and the possible expansions of these were estimated; then new sciences, or new divisions of sciences, or new duties that would need the services of a family or families specially selected and moulded for the purpose, were taken into the account. From this elaborate review of the resources and needs of the population conclusions were carefully drawn as to the number and quality of the children that were required. The problem was easy enough as far as mere extensions of the existing families were concerned. But the creation of new types was a question that tasked the abilities of the wisest to the utmost. The special faculties needed for the new science or art or duty had to be discussed and decided; and especially how far existing faculties would have to be modified or newly combined. Then out of the various families those two had to be chosen, a cross which would produce the required modification or combination. But, as this was still largely of the nature of experiment, more than one effort was made towards each new type, in order that, if one child failed, the others might be available. But the wise creators of new types were rapidly getting surer of their ground; their experiments were growing less of experiments; they could almost foretell to a faculty or tissue the result of the crossing of any two families. And where any quality was unequal to the new duty, first creative surgery was called in to modify or add to the tissue of that part of the brain which was the physical equivalent of the faculty, and afterwards education with its various magnetic and dietary aids was brought to bear on its development. Yet there might be some chance of their new type falling short of its purpose and, to guard against this, several individuals of it were brought forth and trained. It was generally found that all of them were needed to carry out the duties of the new position.