1875.] Dr. F. W. Pavy on the Production of Glycosuria. 53 



to the fluid ounce ; half an hour later still, 10*48 grains ; and again 40 

 minutes after this, 6*31 grains to the fluid ounce. At the completion of 

 the inhalation some blood was collected from the jugular vein, and found 

 to possess an intermediate colour between arterial and venous. On ex- 

 amination for sugar a strong reaction was obtainable ; and through ob- 

 serving this, although no decided indication of the presence of sugar 

 existed in the urine at the time, I was led to anticipate that it would be 

 found, as proved to be the case, later on. 



In the other successful experiment the inhalation was carried on in a 

 deep and active manner for half an hour without any irritation of the 

 air-passages being produced. When discontinued, the urine was found 

 to contain a trace of sugar ; and half an hour later sugar was present to 

 the extent of 5*71 grains to the fluid ounce. 



From observation I have been led to believe that the issue in these 

 experiments with oxygen depends upon the manner in which the process 

 of respiration happens to be carried on. I have frequently noticed that the 

 movements of the chest have been performed in a signally sluggish way. In 

 each of the experiments, on the other hand, where the production of glyco- 

 suria occurred, the breathing was carried on in a strikingly deep and active 

 manner. It is known that the muscular operation Of respiration is ordinarily 

 conducted with an inverse degree of activity to its effect upon the blood. 

 Through the accommodating relation existing, the more effective the oxy- 

 genation of the blood, the less actively are the movements of respiration 

 performed ; and thus, although the animal may be supplied with oxygen 

 instead of air, it does not follow that any altered result should occur. 

 In illustration of this I may state that upon one occasion I placed a guinea- 

 pig in a sealed glass jar and kept a free current of purified oxygen passing 

 through for the space of seven hours, without producing the slightest per- 

 ceptible effect either at the time or afterwards upon the animal. 



Some of my experiments with oxygen have been conducted upon frogs ; 

 and the plan adopted has been to place the animal in a glass jar sealed 

 at the bottom with water, and to pass a current of the gas continuously 

 through it for varying lengths of time. The urine is readily obtained by 

 pressure over the bladder; and by using a small test-tube the amount 

 collected from one animal may be quite sufficient for testing. Many of 

 the experiments have been attended with a negative result ; but in some 

 a faint though distinctly appreciable and in others a fairly strong reac- 

 tion of sugar has been obtained. Three or four hours' time has sufficed 

 for this effect to be noticed. 



Finding that I was dependent in the above mode of experimenting upon 

 the chance manner, as it seemed, in which the process of respiration was 

 carried on, I determined to resort to the performance of artificial respira- 

 tion for the purpose of removing the uncertainty that existed. The 

 artificial-respiration apparatus which for many years past I have been 

 in the habit of using in my laboratory was constructed after my own 



