54 THE WORK OF THE DIGESTIVE GLANDS. 



This we (Madam Schumow-Shnanowski and I) achieved with dogs 

 prepared in a manner similar to that which has been now demonstrated 

 to you. Gastrotomy and cesophagotomy had previously been carried 

 out, the right vagus was cut through below the origin of the inferior 

 laryngeal and heart fibres, the left divided in the region of the neck. 

 A longer or shorter piece of the peripheral end of the latter had been 

 prepared free, placed on a ligature, and for the time being preserved 

 under the skin. After three to four days the stitches were carefully re- 

 moved from the skin and the wound painlessly opened, when the nerve 

 lay free before us. In this way we avoided appreciable discomfort to 

 the animal before exciting the nerve. By such precautions we invariably 

 succeeded in obtaining a secretion of juice from the empty stomach 

 when the nerve was subsequently excited by slow induction shocks at 

 intervals of one to two seconds (so-called " rhythmic excitation "). 



And now that we had the matter under perfect control we attempted 

 to achieve the same thing in the " acute " experiment, that is to say, on 

 a dog prepared at the time, but naturally with the observance of certain 

 precautions. Dr. Uschakoff, in his first experiments, after a speedy 

 but careful tracheotomy, divided the spinal cord below the medulla 

 oblongata with the greatest possible rapidity (a few seconds) in order to 

 prevent all reflex effects on the gastric glands from his further operative 

 procedures. The vagi nerves were now sought out and divided ; an 

 ordinary fistula cannula was brought into the stomach, the food passage 

 ligatured in the region of the neck and also at the pylorus. The 

 animal was then suspended in a standing position in a frame. In his 

 later experiments Dr. Uschakofi* employed a short chloroform narcosis 

 (10-15 minutes duration), during which all the above operations were 

 carried out in great haste. Experiments specially performed with this 

 object on dogs previously gastro- and a\sophagotomised had shown that 

 a chloroform narcosis of such short duration was not followed by any 

 serious interference with the glands or their nerves. Fifteen to twenty 

 minutes after the narcosis the dogs were again lively, ate with greed 

 the food set before them, and, after the usual interval of five minutes, 

 gastric juice of strong digestive power began to flow from the stomach 

 in perfectly normal quantity. 



In dogs prepared as described at one sitting, we proceeded to ex- 

 cite the nerves, and were able to see, as we expected, an undoubted 

 and vigorous effect from the stimulation. This occurred, however, only 

 in half of all the cases. In our later experiments, carried out under 

 narcosis, we obtained a positive result much oftener. In none of the 

 successful cases was the effect of the stimulus seen immediately, it 

 only appeared after the lapse of a preliminary period, during which the 

 excitation remained ineffective. This period lasted from fifteen minutes 



