AND PHYSIOLOGY. 369 



found to be empty ; and it was afterwards ascertained that no 

 child had been born, and consequently no murder committed. 

 The second case is yet more remarkable. A butcher was 

 brought into the shop of Mr. McFarlan, the druggist, from 

 the market place opposite, laboring under a terrible accident. 

 The man on trying to hook up a heavy pbce of meat above 

 his head, slipped, and the sharp hook penetrated his arm, so 

 that he himself was suspended. On being examined, he was 

 pale, almost pulseless, and expressed himself as suffering the 

 acutest agony. The arm could not be moved without causing 

 excessive pain; and in cutting off the sleeve, he frequently 

 cried out : yet when the arm was exposed, it was found to be 

 quite uninjured, the hook having only traversed the sleeve of 

 his coat! !" 



THE SENSE OF VISION. 



DEFINITIONS AND DESCRIPTIONS. 



678. The chief organ of this sense is the eye, although its 

 appendages perform very important secondary functions. 



679. Anatomy of tlie Eye. — The human eye is nearly 

 globular in form, with a diameter a little less than one inch, 

 the lateral diameter being one twentieth of an inch less than 

 the antero-posterior. (Fig. 339, p. 370.) In general struc- 

 ture it is made up of three membranes, and three humors, 

 or transparent media, and is covered on the surface exposed 

 to the air by mucous membrane, which also lines the inside 

 of the lid, so that the two surfaces at some points are always 

 in contact. 



680. Sclerotica. — The membrane which covers the larger 

 portion of the eye is called the Sclerotica, from the Greek 



Give the instance of the butcher. 678. What is the chief organ of sight? 679. What 

 is the shape of the eye ? Its diameter ? Of how many media and membranes ia it 

 made up ? 



