on, Muscular Motion. 
7 
Transverse 
Axis from 
Axis of 
diameter. 
optic nerve. 
vision. 
Twentieth 
Twentieth 
Twentieth 
parts of an 
parts of an 
parts of an 
inch. 
inch. 
inch. 
The eye of a boy 6 ") 
(Natural state 
1 7 ' 2 
17 i 
17 J 
years old, 45 minutes 
after death - - J 
Distended state 
i 7 i+ 
i 7 4 + 
l8 
The eye of a man 25 1 
1 Natural state 
17 4 
17 i 
17 
years old, 1 hour af- 
ter death - - j 
1 Distended state 
17 i 
17 4 
17 1 
The eye of a man 50 1 
| Natural state 
19 
19 
years old, 20 minutes 
after death - 
1 Distended state 
19 
19 
18 ^ 
From these experiments it appears, that the diameters of 
the eye do not always bear the same proportion ; sometimes 
the transverse diameter is the longest, in other eyes it is of the 
same length as the axis of vision ; but when the coats are dis- 
tended, the transverse diameter is diminished, and the axis of 
vision is lengthened. 
This change, however, does not take place at all ages, for 
at 50 it was not met with. 
In these experiments the pressure was made in the most 
unfavourable way for producing the greatest degree of elonga- 
tion in the axis of vision ; it was, however, the least excep- 
tionable mode for ascertaining that such an effect could take 
place ; when the pressure is made laterally and from without, 
the elongation must be still greater ; and the action of the 
