BY DR. LAUDER BRUNTON. 515 



bellum until its further progress is arrested by the point com- 

 ing in contact with the basilar process of the occipital bone. 

 In this way the edge of the chisel is prevented from injuring 

 the anterior motor fibres of the medulla, and thus producing a 

 disturbance of the motor functions which would complicate the 

 experiment. 



Mode of Operation. Place a rabbit in the prone position on 

 Czermak's rabbit-support, and fix the head to the upright at 

 the side. Feel for the occipital protuberance, and make an in- 

 cision over it about half an inch long. Fix the point of the 

 chisel in the middle line of the skull just behind the protube- 

 rance, and bore through the bone, moving the handle of the 

 instrument from side to side, in order to assist its passage, but 

 not pressing with too great a force. When the skull has been 

 penetrated, push the chisel downwards and forwards through 

 the cerebellum in such a direction as to cross a line joining the 

 two auditory meatus (see Fig. 310) until it is stopped by the 

 basilar process, and then gently withdraw it. Remove some 

 of the urine in half an hour or an hour afterwards ( 138), and 

 test it for sugar. 



SECTION IV. DIGESTION IN THE INTESTINES. 



PANCREATIC JUICE. 



163. Pancreatic juice may be obtained either by a temporary 

 or permanent fistula. It is usually stated that the secretions 

 from these two kinds of fistula differ much from each other, a 

 normal juice being obtained only from a temporary fistula, 

 while that yielded by a permanent one is watery and destitute 

 of some of the properties possessed by the other. Ludwig and 

 Bernstein, however, have, by an improved method of making a 

 permanent fistula, succeeded in obtaining a normal juice from 

 it also. 



164. Method of making a Temporary Fistula. In 

 the dog there are two pancreatic ducts, one of which opens into 

 the duodenum along with the ductus choledochus. The other 

 duct, which is larger, and enters the duodenum about two cen- 

 timetres below the one first mentioned, is exclusive!}' employed 

 for the operation. It is not necessary to ligature the first. 

 Bernard prefers for the purpose large dogs, sheep dogs being 

 best, as they are less subject to peritonitis than others. Five 

 or six hours before the operation, the animal should get a large 

 meal of bread and meat. The operation, which must be per- 

 formed as quickly as possible, consists in laying the dog on its 

 left side, and making an incision five centimetres long in the 

 right hypochondrium from the projecting point of the last false 

 rib downwards, parallel with the linea alba. The bleeding 

 should be stopped before the peritoneum is opened. The duo- 



