242 On the Changes produced in Atmospheric Air 

 in the kidney. He was desired to persist in the use of the 

 medicines, which he did at intervals for four or five years, 

 suffering occasionally in a slight degree, but he did not pass 

 any more calculi. He died at the age of seventy-five. On 

 examining the bladder, its whole cavity (the capacity of 

 which was equal to a pint measure) was completely filled 

 with soft, light, spongy calculi, three hundred and fifty in 

 number, and of different sizes, from that of a walnut to a 

 small pea. They were composed of a mixture of uric acid 

 in powder, the phosphates, and animal mucus ; and differed 

 so much from the calculus voided soon after the patient be- 

 gan the use of alkalis, that they appear to have been formed 

 after that period in the manner mentioned by Mr. W. Brantle. 



A gentleman, who was found to have a stone in his blad- 

 der, was persuaded that it was so small that it might be dis- 

 solved, and with this view he took the fossil alkali, both in 

 its caustic and mild state, for about three months ; but at the 

 end of that period the symptoms were increased, and he 

 submitted to have it extracted by an operation. On ex- 

 amining the calculus after it was extracted, the external part, 

 for the thickness of T Vth of an inch, was entirely composed 

 of triple phosphate, in a state of perfect spiculated crystals, 

 so as to present a very rough irritating surface to the internal 

 membrane of the bladder, while the inner parts of the cal- 

 culus were made up of a mixture of uric acid and phosphates, 

 so that the alkali had prevented the formation of uric acid, 

 but the phosphates were deposited more rapidly than before, 



A gentleman, in whose urine the uric acid appears in a 

 solid form, immediately after it is voided, has the same ap- 

 pearance in the urine, even when nine drachms of soda dis- 

 solved in water, impregnated with carbonic acid, are taken 

 in twenty-four hours ; so that in this instance the alkali 

 docs not even counteract the formation of uric acid. 



XXXVII. On the Changes produced in Atmospheric Air and 

 Oxi/ "en Gas hit Respiration. Bi/ W. Allen, Esq., 

 F.R.S., and \V. H. Pepys, Esq.,' F.R.S.* 



T* 



J. he process of respiration, or breathing, is so intimately 



connected with our existence in life, that from its first mo- 



* From Philosophical Transactions for iSOS. F^rt II, 



ments, 



