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In working with the pathogenic microorganisms the 

 student must specially observe the utmost precaution 

 against personal infection. The rule to sterilize every 

 instrument shortly before, and immediately after use, 

 before it has left the hands, must be strictly attended to. 

 Direct contact of the hands with infectious matter must 

 be carefully avoided, and when such contact has taken 

 place prompt disinfection must be resorted to. On no 

 account must lead pencils or glass rods be held in the 

 mouth, or labels moistened on the tongue. Gelatin or agar 

 plates must be set aside for some hours in mercuric chlo- 

 ride (1-1000). Old tube cultures are best sterilized by 

 heating in the steam sterilizer for about one-half hour. If 

 by accident infectious matter is dropped on the table or 

 floor it must at once be covered with mercuric chloride. 

 At the close of the day's work the table must be well 

 washed with the mercury solution, and the hands 

 thoroughly disinfected. 



