94 



evacuation the sac very quickly tilled again, notwithstanding pressure 

 exercised upon it. 



The examination after death showed that the fluid was collected 

 in the expanded tissue of the pia mater, or subarachnoid spaces, 

 about the cauda equina. The pia mater presented appearances of 

 inflammation long past, as well as of that which had probably been 

 the cause of death. The canal in the axis of the spinal cord was 

 distinct in its whole length. Commencing, below a large fourth 

 ventricle, with a diameter of about one-fourth of a line, it gradually 

 widened, till, at the lumbar part of the cord, it had a diameter of a 

 line and a half. Its termination at the end of the cord could not be 

 traced in the confusion of parts caused by the distension and inflam- 

 mation of the membranes. 



III. " On the Oxidation of Ammonia in the Human Body." 

 By H, BENCE JONES, M.D., F.R.S., Physician to St. 

 George's Hospital. Received June 14, 1854. 



In the last edition of Professor Lehmann's Animal Chemistry, 

 vol. ii. p. 363, a very decided opinion is expressed against the con- 

 clusion to which I arrived in consequence of some experiments pub- 

 lished in the Philosophical Transactions for 1 85 1 . 



I considered it proved that ammonia was partly at least converted 

 into nitrous acid in its passage through the body. In opposition to 

 this Professor Lehmann states, 



1st. That the method which I employed must of necessity give a 

 reaction resembling that given by nitrous acid ; his words are, "Es 

 ware nun leicht einzusehen dass schweflige Saure, durch welche be- 

 kanntlich lodwasserstoff zersetzt wird, in die Vorlage ubergeht urid 

 so jene vermeintliche salpetersaure Reaction bedingt." 



2ndly. That when nitric acid was added to urine and it was di- 

 stilled with phosphoric acid instead of sulphuric acid, no trace of 

 blue colour with starch and iodide of potassium could be obtained. 

 " Das nach Anwendung von Phosphorsaure erhaltene Destillat giebt 

 aber auch jene vermeintliche salpetersaure Reaction nicht, ja selbst 

 dann nicht, wenn dem Harn vorher absichtlich einige Tropfen 

 Salpetersaure zugesetzt worden waren." 



