CATGUT SITE OF OPERATION. 53 



Catgut can be sterilized by boiling. One of the best 

 methods in use at the present time is the cumol method. The 

 catgut is dried first in the hot-air chamber or on a sand-bath, 

 and then is boiled in cumol at a temperature of 168 C. for 

 one hour, which kills not only bacteria, but their spores as 

 well. The cumol is evaporated or poured off and the catgut 

 dried at a temperature of 100 C. for two hours. It is then 

 transferred with sterile forceps to sterile test-tubes, and these 

 are plugged with cotton. 



Catgut may also be soaked in a 4 per cent, formalin solu- 

 tion for twenty-four hours ; boiled in water for fifteen min- 

 utes, and preserved in 95 per cent, alcohol to which are added 

 0.1 per cent, of mercuric chloride and 5 per cent, of glyc- 

 erin. Formaldehyde catgut is stronger and less brittle than 

 the old-fashioned chromicized catgut. It is easily tied and 

 the knot does not slip. Pyoktanin catgut is boiled in a solu- 

 tion of pyoktanin. 



Ligatures of silk and silkworm-gut are boiled in water or 

 placed in sterile test-tubes and sterilized in the steam steril- 

 izer by the fractional method for one-half hour each time. 



Dressings are packed loosely in a canvas bag or gauze 

 wrapper, and sterilized in the steam sterilizer by the frac- 

 tional method. The autoclave may also be used. 



Sterile water and sterile salt solution should always be on 

 hand in large quantities in every modern operating-room. 

 They are, of course, sterilized by boiling. 



Drainage-tubes, hand-brushes, etc., are kept in a disinfect- 

 ant solution. A 5 per cent, carbolic acid solution answers 

 very well. 



Site of operation : It is advisable to begin preparing the 

 site of operation the day before operating. If the part is 

 covered with hair, it should be shaved, then thoroughly 

 scrubbed with green soap and water, shaved again, scrubbed 

 again, washed with alcohol followed by ether, sterile water, 

 or bichloride. The part is then covered with a protective 

 dressing. Recently an artificial skin has been devised which 

 is recommended very highly by some operators. It consists 

 of a large sterilized piece of dental rubber, coated on one side 

 with an adhesive substance. It is spread evenly with the 



