IMPORTANT GENERAL RULES 



1. Keep everything clean! 



2. Have a definite place in your desk for each piece of appa- 

 ratus and arrange reagents in order on top of it. 



3. Use cards for keeping records of materials. Each card 

 should have a number corresponding to that of each special object 

 or piece of tissue, and should show the name of the preparation, 

 date, reagents used, time left in each reagent, in short, all data 

 concerning the manipulation of the material. 



4. Jot down in a blank calendar the various things to be done 

 at future dates, such as changing of reagent on tissues, etc., and 

 then go over this memorandum carefully each day when you first 

 come into the laboratory. 



5. Use only clean vessels in preparing reagents, and clean up 

 all glassware while it is yet moist. 



6. Reserve and mark a separate pipette for each of the chief 

 reagents (absolute alcohol, oils, acids, etc.). 



7. In making up solutions, 1 gram of a salt in 100 c.c. of 

 liquid is reckoned ordinarily as a 1 per cent, solution, 3 grams as a 

 3 per cent, solution, etc. A saturated solution contains all of a 

 given substance that the liquid will take up. When a solution is 

 called for without specifying the solvent an aqueous solution is 

 meant. 



8. In weighing salts, always first put paper in the scale pans 

 to protect 'them. 



9. In making solutions or mixtures in which only a small 

 amount of one reagent is used, after mixing, pour back some of 

 the mixture into the small vessel and rinse it thoroughly in order 

 to get all of the original contents out. 



10. When pouring liquids from bottles keep the label of the 

 bottle turned toward the palm of the hand. Do not lay down 

 stoppers but hold them by their tops between the knuckles. 



11. Before leaving the laboratory put away your instruments 

 and clean and put in its place whatever laboratory apparatus you 

 may have been using. 



