On Lesions of the Nervous System producing Diabetes. 53 
performed, Dr. Pavy believed that the functions of the brain may be 
completely destroyed, without placing the liver in the condition no- 
ticeable after actual death, or after lesion of the medulla oblongata. 
On account of the accidental disturbances, —such as implication of the 
medulla oblongata, possibly by concussion, obstruction of the respi- 
ration, and the effects of the great loss of blood sometimes attending 
division of the crura cerebri,—the interpretation of the result is ren- 
dered a little difficult. In an experiment, which proved most con- 
clusive, performed to corroborate the author’s previous observations 
whilst his communication was being writtev, there were none of these 
disturbing circumstances. In a healthy dog, during a period of diges- 
tion, the crura cerebri were completely divided. The animal was 
thereby thrown into a state of unconsciousness, but breathed efficiently 
of its own accord. The urine in an hour and a quarter’s time was 
found perfectly free from sugar. 
After poisoning by strychnine, the effect is the same as after de- 
struction of the medulla oblongata. The circulation being maintained 
by artificial respiration, the urine becomes strongly saccharine. 
Looking to these facts, and to the effect of Bernard’s puncture of 
the fourth ventricle in producing diabetes, the author is led to regard 
the medulla oblongata as a centre, either directly presiding over the 
functional activity of the liver, or indirectly affecting it by altering 
through the medium of another or other organs the condition of the 
blood going to it; and he has endeavoured to establish upon positive 
grounds the channel by which the propagation of the nervous influ- 
ence may take place. It was this line of research that conducted to 
the discovery of the strongly diabetic effect produced by dividing 
certain parts of the sympathetic. 
The medulla oblongata being thus presumed to form a centre 
giving to the liver a force which prevents the saccharine metamor- 
phosis of its hepatine, experiment had already shown that it cannot be 
through the spinal cord or the pneumogastrics separately, that the 
transmission of nervous influence takes place. But an experiment was 
performed to determine the effect of dividing both the spinal cord and 
the two pneumogastries together. The cord was crushed between the 
third and fourth cervical vertebree, and about half an inch of each 
pheumogastric was cut away from the centre of the neck. Artificial 
respiration was performed to keep up the circulation. The urine 
remained entirely free from sugar, and the liver was found in an 
exsaccharine state at the moment of discontinuing the respiration, 
and became strongly saccharine afterwards. 
On next dividing all the nerves in the neck, an operation effected 
by performing decapitation, the result that followed after three 
quarters of an hour’s artificial respiration was strongly saccharine 
urine. After this experiment, and that of division of the spinal cord and 
pneumogastrics, reason was afforded for looking to the sympathetic; 
and from the experiments that have been made and are described, 
the following conclusions have been arrived at. The animal selected 
for observation has been the dog, subsisting upon an animal diet, and 
operated upon at a period of full digestion. 
