TECHNIQUE OF EYE DISSECTIONS 



sected may be placed in a, 5 per cent, formalde- 

 hyde solution, and kept indefinitely. The lens 

 fibres, concentric layers, and lens laminae in 

 such a specimen will always be interesting. 



A lens that has lost its transparency be- 

 cause of hardening in formaldehyde or boiling 

 may be made clear and nearly transparent 

 again in the following way: First: Place the 

 lens in a 50 per cent, alcohol for several hours. 

 Second : Remove the lens, and let it drain on a 

 piece of blotting-paper; then place it in a 75 

 per cent, alcohol. Third: Eemove the lens, as 

 before, then place it in an 85 per cent, alco- 

 hol. The lens may be left in this alcohol from 

 ten to twelve hours, after which length of time 

 it should be removed and drained. Fourth: 

 Place the lens in an absolute alcohol, and leave 

 it there for ten or twelve hours. Several hours 

 longer will not injure the lens, nor interfere 

 with the success of the work. Fifth: Remove 

 the lens from the absolute alcohol. Place it 

 upon a piece of blotting-paper, moving it to 

 another place on the blotting-paper whenever 

 the paper around the lens seems to have taken 



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