1875.] Dr. F. W. Pavy on the Production of Glycosuria. 55 



Through Dr. Richardson, I have since learnt that the active agent of 

 puff-ball smoke was some time back shown, by Thornton Herepath and 

 Snow, to consist of carbonic oxide, a gas which reddens blood in the 

 same manner as oxygen, but which, unlike oxygen, is not easily displaced 

 by the agency of other gases. Now, Dr. Richardson having noticed* 

 that the inhalation of carbonic oxide is followed by glycosuria, our 

 respective observations coincide, and I have no reason to doubt that the 

 circumstances are otherwise than identical ; indeed a comparison of the 

 effects of puff-ball smoke and carbonic oxide enables me to support the 

 conclusion that the action of the former is dependent on the presence of 

 the latter. There is the same kind of anaesthesia, the same red state of the 

 blood contained in the venous system, and the same rapid occurrence of 

 strongly marked glycosuria. No matter whether puff-ball smoke or arti- 

 ficially procured carbonic oxide may be used, within ten minutes or a 

 quarter of an hour after the production of anaesthesia, sugar may be 

 recognizable to a notable extent in the urine ; and a little later I have 

 upon some occasions found that my analyses have indicated the presence 

 of as much as upwards of 30 grains to the fluid ounce. 



Such is the result to which I desire to direct attention ; and I will 

 proceed to explain in what way it appears to me to stand connected with 

 the subject under consideration. 



It is seen that a gas which produces the same physical effect on the 

 blood as oxygen likewise determines the production of glycosuria. The 

 bright scarlet colour belonging to arterial blood is also the colour which 

 is given to blood by the presence of carbonic oxide ; and, furthermore, Dr. 

 Gamgee has shown that the spectral properties of the compound of 

 colouring-matter and carbonic oxide are identical with those of oxidized 

 blood. There is this difference, however, noticeable, which seems to tell 

 in a striking way in relation to glycosuria. The combination of colouring- 

 matter and oxygen (oxy-hsemoglobin) is so feebly maintained that a re- 

 ducing action is readily exerted by the influence of carbonic acid, and 

 hence the facility with which oxidized is converted into deoxidized 

 blood. In the case of carbonic oxide, however, the gas is so much more 

 strongly held, that it is not similarly susceptible of being readily displaced 

 by other gases. As a result of its inhalation the blood becomes charged 

 with it, and, by virtue of the property alluded to, retains it while traver- 

 sing the systemic capillaries. In consequence of this retention it is 

 allowed to reach the liver, and there produce the effect which results in 

 glycosuria. It is to the capacity of retention that I assume may be 

 ascribed the speedy occurrence of glycosuria which follows its inhalation ; 

 and I think it may be surmised, seeing that oxygenated blood acts in a 

 similar way upon the liver, that if it were not for the easy manner in 

 which oxygen is withdrawn from the blood in its passage through the 

 systemic capillaries, the result of its inhalation, even under the form of 

 * Medical Times and Gazette, March 8th, 1862. 



