SOLUTIONS 27 



3. Syringes may be sterilized by filling them with 1 per cent, formalin 

 solution for a few minutes, followed by several washings with sterile 

 water or salt solution. This method is good for syringes having 

 leather or rubber packings and plungers. It is not safe for blood cul- 

 tures, as spore-forming bacteria may escape the sterilizing process. 



4. With all glass or metal syringes, it is best to boil the syringe, 

 especially if a careful aseptic technic is to be employed. The plunger 

 should be removed from the barrel, or else, whether it be of glass or 

 metal, it will expand more rapidly than the accommodation of the barrel 

 will permit. All parts should be placed in a pan or wrapped in gauze, 

 warm water added, and boiling allowed to take place for a minute or 

 so. After cooling the parts are adjusted. 



Wright's method for sterilizing a hypodermic syringe for the ad- 

 ministration of vaccines is given on p. 217. 



5. If infectious material has been used, the syringe, after using, 

 should be washed out and sterilized. The needles should be dried and 

 wired, and a small amount of vaselin rubbed over to prevent rusting. 

 The plunger may likewise be occasionally rubbed with a small quantity 

 of vaselin. Needles may be kept in oil or in absolute alcohol ; usually 

 thorough drying and wiring preserves them in good condition. 



SOLUTIONS 



1. Salt Solution. 0.85 per cent, sodium chlorid in distilled water is 

 best adapted for immunologic work. This solution is prepared readily 

 by dissolving 8.5 grams of salt in a liter of water, filtering, and sterilizing 

 in an Arnold sterilizer for at least one hour. 



2. Sodium citrate in 1 or 2 per cent, solution, made with normal salt 

 solution and not with plain or distilled water, is used to prevent the 

 formation of fibrin in drawn blood and exudates. 



