VACCINE-THERAPY 51 



How to seal One End of a Glass Tube. 



When we desire to have a tube smaller than a test-tube 

 which will be found useful in working out the opsonic power, 

 etc., we take a piece of pipette tubing, and heat it in the 

 middle in the usual way, drawing it out to make a capillary- 

 stem (A). This will give us the makings of two tubes by- 

 breaking the stem in the middle. We now reduce the flame 

 and apply it to the shoulder, rotating the tube in the mean- 

 time with the right and left hands, and when plastic the 

 stem is still further drawn out until it is melted through (B) . 

 Now apply a full flame to the bottom of the tube, and when 



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Fig. 24. — Sealing off One End of a Glass Tube. 



red hot blow down the tube (G). This will make the distal 

 end quite round, and, if too much glass is not left on the 

 bottom, the heat alone will be sufficient to round it off 

 nicely. 



How to make Blood-Capsules (Wright's). 



These are very useful for the examination and collection 

 of blood to obtain the serum in working out the opsonic 

 power of a case. 



Take a piece of glass tubing, draw out into a capillary 

 stem (Fig, 25). 



Now heat the barrel in the middle, draw it out into a stem, 



