202 
PARACENTESIS ABDOMINIS. 
This phenomenon, termed “ Sucussio Hippocratis,” is the most reliable 
symptom of dropsy. 
Tapping the peritoneal sac—rt very simple operation—is effected with 
a trochar of the same strength as is employed in puncturing the intestine. 
There being no danger here, as in puncture of the intestine, of infecting 
the peritoneal cavity from the bowel, and it being easy to disinfect the 
skin, the operation, when carefully carried out, is quite simple, and not 
likely to give rise to peritonitis. Indeed, in former times, when the 
principles of strict asepsis were not understood, the operation was usually 
performed quite successfully without antiseptics. 
The puncture was formerly made at various points. Those through 
the rectum and vagina were soon given up because of the risk of infec¬ 
tion, and the operation is now performed either in the neighbourhood of 
the umbilicus, close to the linea alba, or on one side of the abdominal 
wall, the former being usually selected in small animals. In large 
animals, which are operated on in the standing position, the side of the 
abdominal wall is found a more convenient spot. In cattle the right 
side is chosen, so as not to injure the rumen, which lies on the left; in 
horses the left side, because the caecum is on the right. 
The bowels, being partly filled with gas, float on the fluid, and the 
latter therefore occupies the lower portion of the abdominal cavity, 
which is consequently the point selected for puncture. To make sure, 
the proposed seat of operation should first be percussed, when portions 
of bowel will be recognised by the hollow sound, and fluid by the 
completely dull tone which they respectively give. 
In large animals the operation is performed as follows :—The hair 
being shaved from the point of operation, and the latter disinfected 
(washed with soap and rinsed with a disinfectant), an incision is made 
through the skin with a pointed bistoury or lancet to assist the passage 
of the trochar. This precaution is most useful in excitable animals and 
those with thick skin. Puncture is then effected in the same way as 
puncture of the thorax. The trochar is carefully disinfected and held 
with the handle in the operator’s palm, whilst the forefinger, lying on the 
canula, limits the distance to which the instrument may penetrate. In 
larger animals, 1J to 2 inches may be allowed ; in smaller ones, § to 
1J inches. As soon as the trochar has entered, the stilette is withdrawn, 
and the fluid allowed to discharge. Sometimes a check occurs, and the 
canula requires to be moved in various directions, or cleared of clots by 
passing the stilette or a probe. The precautions required in paracentesis 
thoracis are not so imperative here, and as soon as the fluid ceases to 
flow, the trochar may he removed, and the wound treated as in operating- 
on the chest. 
It is better to lay dogs on the side for operation, as when placed on 
