394 



Prof. Carnelley and Mr. J. S. Haldane. [June 16, 



with chemical reagents under the microscope, the following 

 reactions were observed : — On running in between the slide and 

 cover-slip a solution of iodine in potassium iodide, a brown 

 deposit was obtained. On running in concentrated nitric acid 

 on another slide containing a drop or two of the secretion, a 

 yellow coloration was formed, due to the formation of xantho- 

 proteic acid. These two reactions show the presence of albu- 

 min in the secretion of the organ in question. 

 (d.) The soluble ferment secreted by the columnar cells of the 

 epithelium of the gland was extracted according to the Wittich- 

 Kistiakowsky method (' Pfliiger, Archiv Physiol.,' vol. 9, pp. 

 438 — 459). The isolated ferment converts fibrin into leucin 

 and tyrosin. 



(e.) No glycocholic and taurocholic acids could be detected by the 

 Pettenkofer and other tests. No glycogen was found in the 

 organ or its secretion. 



(/.) The secretion contains leucin and tyrosin. 



Prom these investigations the conclusion to be drawn is that the 

 so-called " liver " of Patella vulgata is similar in function to the 

 pancreas of the vertebrate division of animal life. 



XVII. " The Air of Sewers." By Professor Carnelley, D.Sc., 

 and J. S. Haldane, M.A., M.B., University College, Dundee. 

 Communicated by Sir H. RoSGOE, F.R.S. Received May 21, 

 1887. 



(Abstract). 



Owing to the complaints which had been made of bad smells in 

 the House of Commons a Select Committee was appointed in the 

 spring of 1886 to inquire into the ventilation of the House. By that 

 Committee the authors were instructed to make a series of analyses 

 of the air in the sewers under the Houses of Parliament, and to 

 report thereon. Since then they have examined a considerable 

 number of sewers in Dundee, and have also made a number of 

 laboratory experiments. The object of the research was to obtain 

 a general idea of the amount of some of the more important im- 

 purities in sewer air, and to throw some light on their sources, and 

 the conditions affecting their dissemination. 



After giving a brief resume of the results of the analyses which 

 had been previously made of sewer air, the authors describe the 

 methods they have employed, and the nature and condition of the 

 sewers they have themselves examined. 



As a result of their investigation they found — (1.) That the air of 



