£NT£R0GBNTES1S 43 



sudden thrust of the instrument reduces the pain to nil; its 

 entrance is scarcely felt. 



Fourth Step.— Evacuating the Gas.— The evacuation 

 is usually effected by simply pulling out the trocar from the 

 canula and allowing the gas to escape, without following any 

 special directions. In severe bloats, and especially in severe 

 bloats of several hours' duration, some effort should be made, 

 however, to prevent the gas from escaping too rapidly. The 

 too sudden relief of severe abdominal tension may cause 

 fatal shock. To cope with this situation the outward gush 

 is regulated with the finger at the end of the canula. The 

 flow may be momentarily arrested from time to time as the 

 tension diminishes, so as to bring a gradual instead of a sud- 

 den resumption of the intestinal circulation. 



Sometimes, after a sudden gush of gas, the flow stops as 

 suddenly as it began, before there has been any perceptible 

 diminution of the -distention. The arrest is due to several 

 causes. The canula may slip from the bowel on account of 

 a wide and forcible peristaltic sweep, it may become choked 

 with ingesta, or it may only have penetrated a small intes- 

 tine; or, worse than all, there may be no free gas to evacuate. 

 The distention very often arises not from gas alone, but from 

 an enormous fermenting mass of semi-liquid ingesta that 

 only bubbles through the canula without affording any relief, 

 to the great dismay of the operator. These deviations from 

 the usual situations are met by first reinserting the trocar 

 into the canula to clear its lumen of a possible choke, and if 

 this is not fruitful it is pulled out about two inches and then 

 plunged in in another direction. If results are still negative 

 this may be repeated two or three times ; that is, the trocar 

 is driven into the bowel at different directions in the hope of 

 placing it where gas will flow freely. These punctures must, 

 of course, not be too often repeated, because each one leaves 

 a hole the size of the canula in the bowel, through which 

 bubbling, fermenting ingesta in considerable quantities may 

 find its way into the peritoneal cavity. As the puncturing of 

 a distended bowel without relieving the tension leaves an 

 open hole, it is important, once the operation is begun, to 

 diminish the distention at all hazards. Here, the situation 

 being critical, the left side is attacked in the same manner, 

 and if results are still negative, the rectal route offers the 

 only possible chance to prevent the threatened asphyxiation. 



Fifth Step. — Withdrawing the Canula.— The instru- 

 ment is withdrawn with the fingers of the right hand as the 

 first and second fingers of the left one press down upon the 



