48 ZOOTOMY. 



duodeno-hepatic omentum from the duodenum. In 

 these folds are contained the various vessels passing to the 

 liver ( 93). 



92. The attachment of the spleen to the dorsal wall of 

 the stomach by a broad sheet of peritoneum, the gastro 

 splenic omentum. 



93. The vessels l contained in the duodeno-hepatic 

 omentum, to see which the membrane should be put 

 somewhat upon the stretch. These are the bile duct 

 (Fig. 15, c.b.d) to the animal's right side, the duodenal 



1 For the satisfactory dissection of the blood-vessels the fish should be 

 injected : if not, they may be made out by inflating with air by means 

 of an anatomical blowpipe. I find the following the most convenient 

 method for injection. Have ready four of the movable cannulse usually 

 provided with injecting syringes, or if these are not at hand, four glass 

 tubes drawn out to the form shown in the annexed cut : the end a is 

 for insertion in the vessel, the constriction b for the 

 purpose of preventing any slipping of the ligature, 

 over the end c a short piece of india-rubber tubing is 

 placed, and into this the nozzle of the syringe is pushed. 

 Make a small incision into the conus arteriosus, place 

 one cannula in it, directed forwards, and tie it firmly 

 in its place : tie the second, directed outwards, into 

 the sinus venosus : the third, directed forwards (i.e. 

 towards the dorsal aorta), into the duodenal artery : the 

 fourth, also directed forwards, into the duodenal vein. 

 Fill an ordinary tumbler half full of fine plaster of Paris, 

 coloured with a little of the common " French blue " or ultramarine 

 of the oil shops : fill up the tumbler with water, stir well and 

 immediately strain the liquid through coarse muslin into a second 

 tumbler. Fill the syringe, and inject through all four cannulas suc- 

 cessively. This must be done very rapidly or the plaster will set. On 

 removing the syringe from a cannula, the india-rubber tube should 

 be plugged with a small piece of wood to prevent escape. All the 

 chief vessels are injected in this way : the ventral aorta and its branches 

 from the conus, the systemic veins from the sinus venosus, the dorsal 

 aorta and its branches from the duodenal artery, and the portal vein 

 form the duodenal vein. The caudal and renal portal veins have to be 



