Royal Society. '^17 



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. 



" On the Oxidation of Ammonia in the Human Body." By H. 

 Bence Jones, M.D., F.R.S. 



In the last edition of Professor Lehraann'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 1851. 



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 iibergeht und 

 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 erlialtene Destillat giebt 

 aber auch jene vermeintliche salpetersaure Reaction nicht, ja selbst 

 dann nicht, wenn dem Harn vorher absichtlich einige Tropfen 

 Salpetersaure zugesetzt worden waren." 



It appeared to me undesirable merely to reply to Professor Leh- 

 mann, that I had expressly stated that the indigo and protosulphate 

 of iron tests were used, and gave as decided proof of the presence of 

 nitrous acid in the urine as Price's test gave ; and that sulphurous 

 acid could not have produced the same effect as nitrous acid in these 

 tests. It seemed more desirable to repeat the experiments which 

 had been made in Professor Lehmann's laboratory on the action of 

 sulphurous acid, and on the effect of using phosphoric instead of 

 sulphuric acid in the distillation of the urine. 



I was fortunate enough to obtain the assistance of Mr. Malone to 

 carry on the experiments continuously from day to day, and through 

 the kindness of Dr. Hofmann this was done in the College of Che- 

 mistry. 



1st. On the action of sulphurous acid on starch and iodide of 

 potassium and very dilute hydrochloric acid. 



In England it is by no means well known that sulphurous acid 

 decomposes hydriodic acid. On the contrary, theoretically it should 

 not liberate iodine, and experimentally not only does it not liberate 



