AND HOW TO USE IT. 105 



Goadby's Mass, which is modified from M. Doyer's recipe 

 (Comptus Rendus, 1841). — Saturated solution of bichromate of 

 potash, 8 fluid ozs. ; water, 8 ozs. ; gelatine, 2 ozs. ; saturated solu- 

 tion of acetate of lead, 8 fluid ozs. ; water, 8 ozs. ; gelatine, 2 ozs. 

 The majority of preparations thus injected require to be dried 

 and mounted in Canada balsam. 



The Syringe. — In selecting, the following points should be 

 attended to: — (i) The syringe should be of at least one-ounce 

 capacity, and furnished with two rings at its upper end, one on 

 each side, for the fingers to pass through; (2) it should have 

 three pipes, or cannula, of about 1/16 in., 1/32 in., and 1/64 in. in 

 diameter ; and in order that they may be secured firmly in the 

 vessels whilst making an injection, they should be provided with 

 a pair of arms to pass the ligature round ; (3) the piston should 

 fit the cylinder so accurately, that if the nozzle of the syringe be 

 closed with the finger, or the piston be drawn up, it wUl, on being 

 released, instantly return to its former position ; (4) the syringe 

 should be provided with a stopcock. The cost of such an instru- 

 ment is about 15/-. If the beginner does not desire to go to so 

 much expense, a glass syringe costing about i/- will do very well. 

 The cannulse may be made out of glass tubing, by drawing it to 

 a fine point in a Bunsen's flame, and then cutting off the part 

 required. 



Injecting Apparatus. -^— Place some of the • injection in a 

 wide-mouthed glass jar on a shelf, about five feet above your table ; 

 cut two holes in the cork, which should fit the bottle accurately. 

 In one hole place a small funnel, so that air may get to the inte- 

 rior of the bottle, and should the injection threaten to become 

 exhausted before the completion of the process, some more can 

 be poured in. In the other hole insert a bent glass tube, one end 

 of which should reach in the inside of the bottle to the bottom ; 

 the other end may be left four inches long, and turned over in a 

 good arch. On this end fit about six feet of india-rubber tubing 

 of a size to tightly embrace the glass tube ; in the distal extremity 

 of this tubing fasten a small stop-cock. If now suction be made 

 at this, the injection wiU flow out of the bottle down the tube;- Y.^^""'-^*^ 



* Quekett Journal, March, 1882, p. 17. /rf'^V^l— — -»*w J^ 



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