284 



MALCOLM E. MACGREGOR. 



In order to have a killing-bottle whicli will have the great advantage of chloroform 

 as the poison, the bottle described below is now used. It can be made from 

 ordinary laboratory material, unless a very large-mouthed bottle is required. 



Select an ordinary " boiling- tube " (large form of test-tube), and a large rubber 

 cork which wiU just slide down the inside of the tube, making rather a tight fit. 

 Bore a hole in the centre of the cork so that a small piece of glass-tubing (internal 

 diameter, 2 to 3 mm.) can be forced through. The glass-tubing should be of such 

 a size that it projects about f inch on one side of the cork, and about J inch on the 

 other. 



Now slide the cork into the boiling- tube so that the f inch length of glass tubing 

 projects towards the bottom of the boiling- tube, and force it down until the end 

 of the tubing touches the bottom of the tube. If the rubber cork is a tight fit 



Orcfi'nary 

 cork. 



< _ _ G/ass 

 bo/'/i'ny-tube. 



C/)/crofb/-/7}.~ V^ 





Jif prq/ection 

 offf/ass tubing. 



■f^cf rubber^ cork. 



__ jif. project hn 

 7 of g/ass tubing. 



Fig. 1. A chloroform kiUing-bottle. 



(as it should be) moisten the cork slightly with water and press it down the boiling- 

 tube by the aid of the open end of a small test-tube. Warm the apparatus so as 

 to drive off any moisture that may remain, and when dry it may be charged with 

 chloroform. This is accomplished as follows : — Pour into the boiling-tube suffi- 

 cient chloroform to stand about 2 inches above the upper surface of the rubber 

 cork, and then carefully warm the air-space below the cork over a spirit-lamp. 

 The air will be partly driven out by expansion. Remove the tube from the flame 

 and as the space cools the chloroform will run in to fiU the partial vacuum. Then 

 again heat the bottom of the tube until the chloroform within boils gently, and all 

 the air is driven out by the chloroform vapour. On cooling once more the space 

 will this time be completely fiUed with chloroform. Now invert the tube and 



