1820.] Dr. Hennj on Urinary Calculi. 117 



ful examination of the concretions in the substance of the lungs, 

 Mr. Burns ascertained that each was lodged in a bronchial cell, 

 and was enveloped in a distinct capsule, which admitted of 

 being readily separated from the membrane of the air cell. 

 Indeed in all concretions discovered in the soft parts of the bodv, 

 Mr. Burns informed me that he has uniformly found a peculiar 

 substance containing the sohd substance, and over this another 

 sheath of dense membrane. The inner covering he supposed to 

 belong essentially to the concretion, and the outer one to be 

 formed in consequence of the irritation caused by the presence 

 of an extraneous body. 



Calculi from the Spleen. — For the opportunity of examining 

 these, I was indebted to the same zealous and able anatomist. 

 They were of small size, shaped like a pear, of a yellowish-white 

 colour, and were composed of bone earth, without any portion 

 of the triple phosphate. 



Small Crystals Jormed on the Surface of a cancerous Prepara- 

 tion, kept in S2nrit of Turpentine. — These also I received from 

 Mr. Burns ; and though not strictly belonging to the class of 

 morbid concretions, I mention them here on account of their 

 singular composition. They are in very minute parallelopipe- 

 dons, are fusible when placed on a piece of iron heated below 

 redness, and evaporate in an aromatic smoke. They are very 

 sparingly soluble in water, but more so in alcohol ; and the latter 

 solution, when concentrated, reddens litmus paper. They agree^ 

 therefore, in their properties with the camphoric acid, and fur- 

 nish an instance of the production of that acid under circum- 

 stances not before observed. Whether they had passed through 

 the intermediate state of camphor, which, by well knowa 

 treatment, may be obtained from spirit of turpentine, it is now- 

 impossible to ascertain. Mr. Burns, however, assured me that 

 they may not unfrequently be seen on preparations kept in that 

 fluid ; but never, except when the parts have been imperfectly 

 dried before being immersed in it. It is probable, therefore,, 

 that they may be found under similar circumstances in other 

 anatomical collections. 



Mancluiter, Dec. 16, 1 SIS. 



Article V. 



Memoir on Sulphuric Ether.* By John Dalton. 



In my essay on the force of steam, read before the Society m 

 1801, and published in the fifth volume of the Memoirs, I stated 

 «ome experiments on the force of vapour from sulphuric ether, 



• Read before the Literary Socic:y at Maochcstcr, April 16, 1819. 



