Assuming that the emotions are the effects and not the causes of what are usually reckoned as their “expression,” it seems evident that a given movement or set of movements must uniformly, at least in the same subject, give rise to the same feeling, and that in the case of opposite emotions such as joy and grief, hope and fear, the more intense the emotion, the more unlike must be the actions from which it arises. Neither of these is the case. On the contrary, it would seem to be the fact that the actions accompanying emotion tend to become more alike in proportion to its intensity. It is not at all uncommon for people to weep from excess of joy as well as of grief. Pallor and trembling are frequent accompaniments of the extremes of hope as well as fear. The naturalist Wallace gives an account of his feelings on capturing a rare and beautiful butterfly, which is worth quoting in this connection: “The beauty and brilliancy of this insect are indescribable, and none but a naturalist can understand the intense excitement I experienced when I at length captured it. On taking it out of the net and opening the glorious wings, my heart began to beat violently, the blood rushed to my head, and I felt more like fainting than I have done when in prospect of immediate death. I had a headache the rest of the day, so great was the excitement produced by what will appear to most people a very inadequate cause” (“Malay Archipelago,” p. 342). Here it is evident that a feeling of intense exultation gave rise to sensations very similar, to say the least, to those of extreme fear. One other argument brought forward by the author deserves special notice in this connection: