THE CANAL OF PETIT 



THE canal of Petit is a "triangular space 

 around the circumference of the lens." That 

 it can be "inflated through a fine blowpipe in- 

 serted through the suspensory ligament, " is 

 the usual direction given. However, the ordi- 

 nary "fine blowpipe" is much too large and 

 too dull to be inserted through the suspensory 

 ligament. Take a long medicine-dropper (5 

 or 10 cents at a drug store), or a pipette, 

 and heat it until it is red hot over an alcohol 

 lamp or a Bunsen burner; hold one end with 

 one hand and the other end with a pair of 

 tweezers. As the glass becomes white hot 

 pull the tube apart. This will leave the places 

 of separation pointed and sharp-edged. Use 

 the larger of the two pieces. Sometimes the 

 point or tapering end of the tube is too long 

 and the bore too small. All that is necessary 

 is to first mark off with a file the length to be 

 broken off, and then that length may be snap- 



35 



