The sanitary expert, of merely human stock, could attack the problem in only one way. He must have a through-current of air, impelled either mechanically or automatically; and he must have heating-apparatus acting within the building itself, or warming the incoming draught of air. But the bees work on totally different principles. They will have nothing to do with the through-current system of ventilation. If the ingenious bee-master pierce air-holes in the walls of a hive, the bees will spend the night in carefully stopping them up again. In the old bee-garden we saw the fanning-army drawing out the impure air. These bees had their heads pointing towards the entrance; but, inside the hive, there was another army of fanners, facing the opposite way, and thus helping to drive the same sidelong current. Throughout nearly the whole interior of the hive on hot days fanning-bees can be seen, all helping to keep up this movement. The result is that the pure air, being sucked in at one side of the entrance, flows round the hive and travels out at the other side, much as a rope goes over a pulley-block. The swiftest current of air keeps to the walls and roof of the hive, the air in the centre being changed more slowly. Thus the honeycombs, which are always in the upper stories, lie in the full stream, and the moisture, which the maturing honey is continually giving off, is carried rapidly away; while the brood-combs, lying in the lower, central part, are ventilated more slowly, the air being thoroughly warmed before it reaches them. The larger the fanning-army is, the more swiftly flows the air, and the faster the heat of the hive is carried off. In this way the bees can regulate the hive-temperature to the requirements of the moment, putting more numerous gangs to work in the hottest season, or stopping the fanners altogether in mid-winter, when the natural, buoyant heat-exhalation from the cluster is sufficient to keep up the gentle circulation which then is alone needed. Sometimes, when the colony is unusually large, the fanning-party will be divided into two detachments, one at each side of the entrance, leaving the centre for the inflow of air. In this case a double-loop system of ventilation appears to be formed. CHAPTER VII THE GENESIS OF THE QUEEN IT has been said that the ways of the honey-bee are nearly all subject to variation—that in bee-life there are few hard-and-fast, undeviating laws. The rule, of one queen-mother only to each hive, appears to be more absolute than any other, yet it is not without its exceptions. Well authenticated instances are on record where two queens have existed amicably in the same hive, each laying her daily quota of eggs unmolested by the other, and, apparently, with the full approval of the hive-authorities.