PREPARATION OF INSTRUMENTS, ETC. 215 



these put in a glass beaker. The bottom of the beaker is 

 covered with a layer of cotton on which the catgut rests. The 

 beaker is heated with a Bunsen burner over a sandbath. The 

 top of the beaker is covered with a piece of cardboard. Through 

 a hole in the center of the cardboard a thermometer passes. 

 Heat is now applied to the sandbath, and the temperature 

 of the catgut slowly raised to 80° C. In this manner all mois- 

 ture is driven out of the catgut. This degree of heat is main- 

 tained for one hour. Cumol* at a temperature of 100" C. 

 is now added to the beaker, completely covering the catgut. 

 The beaker should be covered with copper-wire netting to 

 prevent ignition of the cumol, which is very inflammable. 

 The temperature is then increased to 165° C, and kept at this 

 point for one hour. The fluid is now poured off, and the 

 catgut allowed to dry in the beaker on the sandbath at a tem- 

 perature of 100° C. for two hours. It is then transferred to 

 sterile jars or test-tubes until needed, or it may be preserved 

 in sterile alcohol. 



Formaldehyde catgut.^ Three-quarter-inch glass spools are 

 notched on each flange. The catgut is wound upon the spool 

 tightly in one layer, and evenly, the ends passing over the 

 flange of the spool in the notch; the longer end, after passing 

 through the notch, goes through the barrel of the spool and 

 is securely tied to the shorter end which has passed over the 

 other notched flange. By thus winding the gut there will be 

 enough for one or two ligatures or sutures of good length. 

 Gut prepared by this process tends to contract forcibly, and 

 on account of this strain must be held securely or it will shrink 

 and be useless. The object of winding in a single layer, evenly, 

 is to prevent overlapping or crossing of one strand over an- 

 other. If in the process of soaking in formaldehyde and the 



* Cumol is a fluid hydrocarbon, with a boiling-point somewhat above 165° C. 

 It dissolves the fat in catgut. After boiling it has a brown color, 

 t Frederick. American Journal Obstetrics. Vol. LXXXIX. 1899. 



