To come to closer quarters with the relationship which holds good between the external and internal elements, it appears that, when the stimulus evokes or intensifies the want or need, this is probably effected by efferent waves which call the organs or parts into tonic action, of which the animal becomes conscious through the afferent messages which come in from them to the sensory centres; in much the same way as the whiff from the kitchen takes effect on the salivary and other glands, and throws the organs of digestion into a felt preparedness for the fulfilment of their functions. But it may have other and more indirect consequences. When the moor-hen dived to escape from the obtrusive puppy, his heart-beat was probably affected; he had, perhaps, an uncomfortable sinking in his gizzard; his breathing was short and laboured; and he experienced creepy sensations in the skin and around the feather-roots. Such we may suppose were the accompaniments or sources of the emotional state of fear or alarm. And they presumably entered with no little vividness into the conscious situation at the moment of instinctive action. In all those cases in which the behaviour is associated with such an emotional state as anger or fear, the external stimulus seems to produce widely-spread effects on the glands, respiratory organs, heart and blood-vessels, skin and other parts, as well as the more direct response in productive action. And all this must enter into the conscious situation, contributing largely, as we shall hereafter see, to the emotions in their instinctive origin. Enough has now been said to indicate with sufficient clearness the kind of co-operation and mutual relationship which subsists between the external and the internal factors in the conscious situation which leads to instinctive behaviour. We have seen that, not improbably, some organic prompting is always present in greater or less degree. But the question still remains whether anything like a definite and particular external stimulus is in all cases a necessary factor.