Basically, what I've gotten from it so far is that Bergson thinks that laughter is a purely intellectual affair, and that emotion cannot enter into it, especially emotions like sadness, fear, hate, love, etc. I tend to agree, but I think that there may be an exception that proves the rule, it's called insanity.

Early in the essay, Bergson gives an example or a man falling down, this can be funny because the man should have noticed the rock in his path, but he failed to be flexable enough (mentally or physically) to avoid the fall. But what makes it funnier is if the man falling down was waxing philosophic about something, then he falls over a rock. Haha, right? Kind of. Then Bergson reminds us of Don Quixote, perpetually staring at the stars and one of the great comic characters in Literature.

I heard of a study done recently with primates which seemed to show that laughter was not what we may assume it is. It seems that our distant cousins make a sound akin to laughter when they are in the presence of their superiors.

It makes sense to me. Laughter may be our way of sucking up to those whom we are wanting to impress. Think about the last time you giggled when you were intent on fitting in.

In relation to what dannye mentions, babies laugh long before they can talk. A study at the University of Maryland has found that laughter may actually be a remnant of the earliest primate communication and not related to speech at all. "Laughter is a tool to study vocal evolution", as chimpanzees laugh too, though in a manner quite different from the universal human "ha".¹ Their predominantly four-legged locomotion prevents the control over their breath which is necessary for human-sounding laughter as well as vocal speech.

For further reading, see "A serious article about laughter" by Sara Abdulla in Nature Science Update:
http://www.nature.com/nsu/981217/981217-2.html

¹Robert R. Provine, University of Maryland, Baltimore County. p. 30, "Speaking of Laughter". National Geographic. May 2001, Vol. 1999, No. 5.

A string of laughter, worn around her wrist. Beads of smiles, anecdotes, and jokes click together with a warm tone and a tiny bell chimes at the join. How she came by it I know not, in a tiny shop of curios, or a gift from a faerie. It's beautiful; bright colours all mingled in apparent confusion. I cannot help but smile as she catches me staring at it. She catches my eye and all at once I'm lost in her own smile as I laugh, and she laughs with me. It sounds for all the world like that tiny bell.

Laugh"ter (?), n. [AS. hleahtor; akin to OHG. hlahtar, G. gelachter, Icel. hlatr, Dan. latter. See Laugh, v. i. ]

A movement (usually involuntary) of the muscles of the face, particularly of the lips, with a peculiar expression of the eyes, indicating merriment, satisfaction, or derision, and usually attended by a sonorous and interrupted expulsion of air from the lungs. See Laugh, v. i.

The act of laughter, which is a sweet contraction of the muscles of the face, and a pleasant agitation of the vocal organs, is not merely, or totally within the jurisdiction of ourselves. Sir T. Browne.

Archly the maiden smiled, and with eyes overrunning with laughter. Longfellow.

© Webster 1913.