384 OPERATIONS ON THE DIGESTIVE APPABATUS. 



the effusion, has been successfrilly added as a means of preventing 

 the return of the fluid. 



In selecting the place where the operation is to be performed, 

 Brogniez, Degives, Peuch and Toussadnt advised the middle of 

 the linea alba, at an equal distance from the xiphoid cartilage of 

 the sternum and the anterior border of the pubis; Zundel, on the 

 coiitrary, recommends " a puncture on the right side in rumiuants, 

 on the left in horses, on a point at an equal distance between the 

 umbiUous and the external angle of the Uium, about on a Hne run- 

 ning from the stifle towards the cartilage of the last rib." He 

 adds, however, "to select the point where the liquid is most de- 

 tectable and fluctuation better felt." 



A trocar of the size of a quill for large animals, and an aspirator 

 for the small, are the only instruments required. In operating on 

 large animals, they are kept standing, while small animals are laid 

 upon a table and placed slightly on their backs. Placing himself 

 on the left side of the animal, after having selected the place 

 where the puncture is to be made, the operator, holding the trocar 



Fio. 371.— Holding the Trocar in ParacentlieBls. 



full in his hand and hmiting its action by keeping his fingers a 

 short distance from the point of the instrument, pushes it by a 

 rapid and firm pressure through the thickness of the abdominal 

 walls, unto, he feels that he has overcome their resistance, and that 

 the instrument has passed into the cavity. The trocar is then 

 withdrawn from its canula and the fluid escapes through the tube. 

 Director Degives describes another modus operandi, which he 

 caUs subcutaneous, in which the opening of the skin does not cor- 

 respond with the division of the deeper musoiilar layers, and by 

 which the opening becomes covered by the skin. To effect this 

 the skin is drawn a little aside, then punctured, or a large fold of 

 the tegument is taken hold of, and the puncture made at its base. 

 In either case, when the skin is loosened, its retraction completely 

 closes the abdominal opening. 



