ANATOMY OF THE EYEBALL. 



45 



will be seen by the following measurements of its various 

 diameters ; but the prominence of its anterior sixth gives the 

 greatest diameter in the antero-posterior direction. 



The form and dimensions of the globe are subject to 

 considerable variations after death, by evaporation of the 

 humors, emptying of vessels, etc., and there is no way in 

 which the normal conditions can be restored. 1 The most 

 exact measurements are those made by Sappey. As an illus- 

 tration of the post-mortem changes in the eye, Sappey men- 

 tions comparative measurements made three hours and twen- 

 ty-four hours after death, the results of which presented very 

 considerable differences. 



In measurements made by Sappey, apparently with great 

 care and accuracy, from one to four hours after death, of the 

 eyes of twelve adult females and fourteen adult males of dif- 

 ferent a^es, the following mean results were obtained : a 



o s O 



From these results, it is seen that the diameters are all 

 less in the female than in the male. The antero-posterior 

 diameter is the greatest of all, and the vertical diameter is 

 the least. The measurements at different ages, not cited in 

 the table just given, show that the excess of the antero-poste- 

 rior diameter over the others is diminished by age. 



Sclerotic Coat. The sclerotic is the dense, opaque, fibrous 

 covering of the posterior five-sixths of the eyeball. Its thick- 

 ness is different in different portions. At the point of pene- 



1 It is for the above reason that we reject the measurements made by Krause, 

 which are so often cited in works on the anatomy and physiology of the eye. 



2 SAPPEY, Traite d'anatomie, Paris, 1871, tome iii., p. 708. 



