I am strongly persuaded that the decay of many flourishing stocks, even when managed with great care, is to be attributed to the fact that they have become enfeebled by "close breeding," and are thus unable to resist the injurious influences which were comparatively harmless when the bees were in a state of high physical vigor. I shall, in the chapter on Artificial Swarming, explain in what way, by the use of my hives, the stock of bees may be easily crossed, when a cultivator is too remote from other Apiaries, to depend upon its being naturally effected. THE WORKERS OR COMMON BEES. The number of workers in a hive varies very much. A good swarm ought to contain 15,000 or 20,000; and in large hives, strong colonies which are not reduced by swarming, frequently number two or three times as many, during the height of the breeding season. We have well-authenticated instances of stocks much more populous than this. The Polish hives will hold several bushels, and yet we are informed by Mr. Dohiogost, that they swarm regularly, and that the swarms are so powerful that "they resemble a little cloud in the air." I shall hereafter consider how the size of the hive affects the number of bees that it may be expected to produce. The workers, (as has been already stated,) are all females whose ovaries are too imperfectly developed to admit of their laying eggs. For a long time, they were regarded as neither males nor females, and were called Neuters; but more careful microscopic examinations have enabled us to detect the rudiments of their ovaries, and thus to determine their sex. The accuracy of these examinations has been verified by the well-known facts respecting _fertile workers_.