the blood-vessels of the beam now begins to languish, and the velvet dies and peels off, leaving the hard, bony substance exposed. Then is the time for fighting, when the stags challenge each other to single combat, while the hinds stand timidly by. But when the period of battle is over, and the wars and loves of the year are past, the bone beneath the burr begins to be eaten away, through the activity of certain large bone-absorbing cells, and, the base of attachment being thus weakened, the antlers are shed; the scarred surface skins over and heals, and only the hair-covered pedicel of the antler is left. [Illustration: FIG. 5.--Wapiti with velvet shredding off.] We have no reason to suppose that this corporate cellular behaviour, involving the nicely adjusted co-operation of so vast an army of organic units, is under the conscious guidance of the stag. And yet how orderly the procedure! how admirable the result! Nor is there an organ or structural part of the stag or any other animal that does not tell the same tale. This is but one paragraph of the volume in which is inscribed the varied and wonderful history of organic behaviour in its corporate aspect. Is it a matter for wonder that the cause of such phenomena has been regarded as “a mystery transcending naturalistic conception; as an alien influx into nature, baffling scientific interpretation”? And yet, though not surprising, this attitude of mind, in face of organic phenomena, is illogical, and is due partly to a misconception of the function of scientific interpretation, partly to influences arising from the course pursued by the historical development of scientific knowledge. The function of biological science is to formulate and to express in generalized terms the related antecedences and sequences which are observed to occur in animals and plants. This can already be done with some approach to precision. But the underlying cause of the observed phenomena does not fall within the purview of natural science; it involves metaphysical conceptions. It is no more (and no less) a “mystery” than all causation in its last resort--as the _raison d’être_ of observed phenomena--is a mystery. Gravitation, chemical affinity, crystalline force,--these are all “mysteries.”