Chap. IX. REFLECTION. 225 



dangerous from the presence of Indians, how incessantly, 

 yet as it appeared unconsciously, the half-wild Gauchos 

 closely scanned the whole horizon. Now, when any one 

 with no covering on his head (as must have been abo- 

 riginally the case with mankind), strives to the utmost 

 to distinguish in broad daylight, and especially if the 

 sky is bright, a distant object, he almost invariably con- 

 tracts his brows to prevent the entrance of too much 

 light; the lower eyelids, cheeks, and upper lip being at 

 the same time raised, so as to lessen the orifice of the 

 eyes. I have purposely asked several persons, young 

 and old, to look, under the above circumstances, at dis- 

 tant objects, making them believe that I only wished 

 to test the power of their vision; and they all behaved 

 in the manner just described. Some of them, also, put 

 their open, flat hands over their eyes to keep out the 

 excess of light. Gratiolet, after making some remarks 

 to nearlv the same effect, 5 says, " Ce sont la des atti- 

 tudes de vision difficile." He concludes that the muscles 

 round the eyes contract partly for the sake of excluding 

 too much light (which appears to me the more impor- 

 tant end), and partly to prevent all rays striking the 

 retina, except those which come direct from the object 

 that is scrutinized. Mr. Bowman, whom I consulted on 

 this point, thinks that the contraction of the surround- 

 ing muscles may, in addition, " partly sustain the con- 

 sensual movements of the two eyes, by giving a firmer 

 support while the globes are brought to binocular vision 

 by their own proper muscles." 



As the effort of viewing with care under a bright 

 light a distant object is both difficult and irksome, and 



5 ' De la Physionomie,' pp. 15, 144, 146. Mr. Herbert 

 Spencer accounts for frowning- exclusively by the habit 

 of contracting the brows as a shade to the eyes in a bright 

 light: see 'Principles of Physiology,' 2nd edit. 1872, p. 546. 



