Till/lit/-: Neuromotor Apparatus in l-'ufilnhx 415 



undue presv ii re and without injury in order to study the movements 

 of organelles and cyclosis phenomena. Needles inadi 1 of -lena ^lass 

 were found to lit- very suitable for general purposes and especially 

 useful in performing t ranseetions and the excision of parts. But even 

 more serviceable were the needles drawn from a hard quality of Pyrex 

 and glass tubing. A s])ecial mixture of this glass may be obtained 

 from the Corning Glass Co., Corning. N. Y. This is less flexible than 

 the .lena glass and apparently not as fragile. For making narrow 

 incisions and the excision of organelles, quartz needles are quite 



L 



d 



Fig. A. Types of glass needles used in microdissection. 



superior in every respect. The costliness of this material becomes 

 neu'lifjrilile if the needles are drawn from lulling that is about one half 

 the diameter of a pin. then sealed with "orange stick" in a handle 

 made of ordinary glass tubing. In fact. I have come to use this 

 method also in making needles of Jena and I'yrex glass. These were 

 drawn in a very small alcohol flame, but an oxygen-gas or oxy-acetylene 

 flame is necessary for making quartz needles. The finest points were 

 obtained by completing the needle not in but quite near the flame. 

 Muscular sense is more dependable than eyesight for drawing very 

 fine points, some of which, especially those of quartz, are less than a 

 micron in diameter. The shape of what may be called the shank of 

 the needle was found to be of considerable importance. The figures 



