52 Dr. F. W. Pavy on the Production of Glycosuria. [Nov. 25, 



expired gas to be expelled without re-entering the balloon. In this way 

 the respiration of oxygen could be easily kept up as desired. 



I found that when the gas was breathed without being purified, it 

 acted as a powerful irritant upon the respiratory passages — exciting 

 cough, difficulty of breathing (apparently from spasmodic contraction of 

 the bronchial tubes), and a profuse flow of mucous secretion. The cough 

 and excessive secretion continued for two or three days and showed that 

 bronchitis had been set up. I at first attributed these symptoms to the 

 presence of chlorine, for the gas possessed what appeared to be a chlo- 

 rinous odour. On testing for chlorine, however, no reaction was pro- 

 curable. Ozone was then looked for, and a strongly marked indication of 

 its presence obtained. Acting upon this information, the gas was passed 

 over peroxide of manganese in a granulated state, and was found to be 

 completely deprived of both chlorinous odour and irritating effect upon 

 the respiratory passages. It could now be breathed without any incon- 

 venience whatever being noticeable. Passage through water also to some 

 extent diminished its odour and irritant action. While, therefore, ozone 

 acts as a powerful irritant upon the air-passages, oxygen is devoid of any 

 irritating property. 



The observations above recorded were made in 1874. In the second 

 supplement to Watt's ' Dictionary of Chemistry ' (1875), I find under the 

 article " Ozone " that the chemical part of the question has recently 

 formed the subject of discussion by others. Special properties are spoken 

 of as belonging to the gas evolved from a mixture of chlorate of potash 

 and peroxide of manganese ; and while some attribute these to the presence 

 of chlorine, Witt, in harmony with my own observations, affirms that 

 they are due to ozone and not to chlorine. 



With these preliminary remarks I come to the description of the results 

 obtained by the respiration of oxygen in relation to the subject of this 

 communication. 



Amongst several experiments conducted upon the dog, I have met with 

 the production of saccharine urine upon two occasions, while in the case 

 of the others a negative result was yielded. 



In one of the successful instances the animal was breathing the gas for 

 55 minutes. It took deep inspirations, and no irritation was excited, nor 

 did any subsequent ill-effect arise. Indeed all that wag specially notice- 

 able, besides the deep breathing, was that at the end of the 55 minutes 

 a state of apnoea was induced, such as is known to be occasioned by in- 

 creased respiratory action. It was from this occurrence that the inhala- 

 tion of oxygen was discontinued, as I felt apprehensive about the issue. 

 In the course of a short time, however, the animal began to breathe in a 

 natural way, and showed no signs of disturbance. The urine was examined 

 at the commencement of the experiment, and gave no reaction of sugar. 

 At the end of the 55 minutes there was also no decided indication of the 

 presence of sugar ; but half an hour later it contained 9*6 grains of sugar 



