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EXPERIMENTAL PHARMACOLOGY 



into the end of a small board should have their heads filed 

 off so the bent wire clip can be easily removed. 



Brass Arterial Cannulas. Fig. 384 shows the method 

 used for making small brass arterial cannulas. A round 

 lorass rod of suitable size is held in the lathe chuck and 

 turned down to the right size and shape. After the out- 

 side of the cannula is entirely finished then a very small 

 drill is passed through the cannula (from the small end). 

 The cannula can then be cut off to the proper length and 

 again placed in the chuck in a reversed direction when a 

 larger drill can be run down the large end of the cannula to 

 near the shoulder. By this means exceedingly strong and 



Turned 

 brass cannula 

 held in laHie chuck 



Chuck in tail stock 



Fig. 38-4. Method for making very small brass cannulas. (For discussion see text.) 



small pointed cannulas can be made. They are much more 

 durable than similar glass ones but hardly so satisfactory 

 for most purposes. Many sizes can, however, be madeand 

 since these metal cannulas can be soldered into brass tubes 

 in pairs or in any other desired fashion they often can be 

 used for a variety of purposes, and also in laboratories 

 where similar glass cannulas are wholly unobtainable. 



Stands and Castings. Fig. 385, which shows a stand with 

 a right-angled base, may be taken as typical of a large 

 number of articles which may be secured cheaply and easily 

 in the laboratory. This stand (which is exceedingly satis- 

 factory in practice) was obtained by first making a wooden 

 pattern of the form and dimensions indicated in the illus- 

 tration. This pattern was then sent to a foundry where 



