The involuntary signs, such of them as are display’d upon the countenance, are of two kinds. Some make their appearance occasionally with the emotions that produce them, and vanish with the emotions: others are formed gradually by some violent passion often recurring; and, becoming permanent signs of this prevailing passion, serve to denote the disposition or temper. The face of an infant indicates no particular disposition, because it cannot be marked with any character to which time is necessary. And even the temporary signs are extremely aukward, being the first rude essays of Nature to discover internal feelings. Thus the shrieking of a new-born infant, without tears or sobbings, is plainly an attempt to weep. Some of the temporary signs, as smiling and frowning, cannot be observed for some months after birth. The permanent signs, formed in youth while the body is soft and flexible, are preserved entire by the firmness and solidity which the body acquires; and are never obliterated even by a change of temper. Permanent signs are not produced after a certain age when the fibres become rigid; some violent cases excepted, such as reiterated fits of the gout or stone through a course of time. But these signs are not so obstinate as what are produced in youth; for when the cause is removed, they gradually wear away, and at last vanish. The natural signs of emotions, voluntary and involuntary, being nearly the same in all men, form an universal language, which no distance of place, no difference of tribe, no diversity of tongue, can darken or render doubtful. Education, though of mighty influence, hath not power to vary or sophisticate, far less to destroy, their signification. This is a wise appointment of Providence. For if these signs were, like words, arbitrary and variable, it would be an intricate science to decipher the actions and motives of our own species, which would prove a great or rather invincible obstruction to the formation of societies. But as matters are ordered, the external appearances of joy, grief, anger, fear, shame, and of the other passions, forming an universal language, open a direct avenue to the heart. As the arbitrary signs vary in every country, there could be no communication of thoughts among different nations, were it not for the natural signs in which all agree. Words are sufficient for the communication of science, and of all mental conceptions: but the discovering passions instantly as they arise, being essential to our well-being and often necessary for self-preservation, the author of our nature, attentive to our wants, hath provided a passage to the heart, which never can be obstructed while our external senses remain entire.