Another illustration of the same principle is exhibited in the chapter on Habit, where it is seen that the power of pleasurable emotions increases by repetition, while painful emotions decrease when the good to be secured by their agency is attained. Thus _fear_ seems to protect from danger till caution and habit render it needless, and then it decreases. And so of other painful emotions. It is interesting to trace the same design in the constitution of minds in _regard to each other_. We find that the purest and highest kind of happiness is dependent on the mutual relations of minds. Thus the enjoyment resulting from the discovery of intellectual and moral traits in other minds--that resulting from giving and receiving affection--that gained by sympathy, and by being the cause of happiness to others, and that resulting from conscious rectitude, all are dependent on the existence of other beings. Now we find that minds are relatively so constituted that _what one desires, it is a source of happiness in another to bestow_. Thus one can be pleased by the discovery of certain traits in other minds, while, in return, the exhibition of these traits, and the consciousness that they are appreciated, is an equal source of enjoyment. One mind seeks the love of others, while these, in return, are desiring objects of affection, and rejoice to confer the gift that is sought. The desire of knowledge or the gratification of curiosity is another source of pleasure, while satisfying this desire is a cause of enjoyment to those around. How readily do mankind seize upon every opportunity to convey interesting news to other minds! Again: we find that, both in sorrow and in joy, the mind seeks for the sympathy of others, while this grateful and soothing boon it is delightful to bestow. So, also, the consciousness of being the cause of good to another sends joy to the heart, while the recipient is filled with the pleasing glow of gratitude in receiving the benefit. The consciousness of virtue in acting for the general good, instead of for contracted, selfish purposes, is another source of happiness, while those who witness its delightful results rejoice to behold and acknowledge it. What bursts of rapturous applause have followed the exhibition of virtuous self-sacrifice for the good of others from bosoms who rejoiced in this display, and who could owe this pleasure to no other cause than the natural constitution of mind, which is formed to be made happy both in beholding and in exercising virtue. This same beneficial economy is manifested in a close analysis of all that is included in the affections of _love_ and _gratitude_. It has been shown that, in the commencement of existence, the young mind first learns the sources of good and evil to self, and its sole motives are desire for its own enjoyment.