GENERAL LABORATORY RULES 91 



bacteria, such as blood serum, potato, bread paste, etc., can be 

 treated in the same manner with excellent results. 



General Laboratory Eules. On the working bench of every 

 bacteriologist there should be a large dish of 1-1000 solution of 

 mercuric chloride in water. Into this all tubes, vessels, plates, 

 hanging-drop cultures, etc., which have contained bacteria and 

 with which he has finished, ought to be at once plunged (in the 

 case of tubes, the tube and plug should be put in separately). 

 On no account whatever are such infected articles to be left 

 lying about the laboratory. The basin is to be repeatedly 

 cleaned out. All the glass is carefully washed in repeated 

 changes of tap water to remove the last trace of perchloride of 

 mercury, a very minute quantity of which is sufficient to inhibit 

 growth. Old cultures which have been stored for a time, and 

 from which fresh sub-cultures have been made, ought to be 

 steamed in the Koch's steriliser for two or three hours, or in the 

 autoclave for a shorter period, and the tubes thoroughly washed 

 out. Besides a basin of mercuric chloride solution for infected 

 apparatus, etc., there ought to be a second reserved for the 

 worker's hands in case of any accidental contamination. When, 

 as in public-health work, a large number of tubes are being daily 

 put out of use, they may be placed in an enamelled slop-pail, 

 and this when full is placed in the steam steriliser. 



A white glazed tile on which a bell-jar can be set is very 

 convenient to have on a bench. Infective material in watch- 

 glasses can be placed thus under cover while investigation is 

 going on, and if anything is spilled the whole can be easily 

 disinfected. In making examinations of organs containing 

 virulent bacteria, the hands should be previously dipped in 

 1-1000 mercuric chloride and allowed to remain wet with this 

 solution. No food ought to be partaken of in the laboratory, 

 and pipes, etc., are not to be laid with their mouth-pieces on 

 the bench. No label is to be licked with the tongue. Before 

 leaving the laboratory the bacteriologist ought to wash the 

 hands and forearms with 1-1000 mercuric chloride and then 

 with yellow soap. In the case of any fluid containing bacteria 

 being accidentally spilt on the bench or floor, 1-1000 mercuric 

 chloride is to be at once poured on the spot. The air of the 

 laboratory ought to be kept as quiet as possible. 



