466 



8. The office of the vasa aberrantia, which are so numerous in 

 the transverse fissure of the human liver and in the larger portal 

 canals, appears to he similar to that of the cavities in the walls of 

 the ducts. It is worthy of remark, that the network of vessels 

 ramifying so abundantly in the coats of the gall-bladder, in the 

 transverse fissure, and in the larger portal canals, are arranged in a 

 similar manner, each branch of artery being accompanied by two 

 branches of the vein. 



9. The liver is therefore a true gland, consisting of a formative 

 portion and a system of excretory ducts directly continuous with it. 

 The secreting cells lie within a delicate tubular network of base- 

 ment membrane, through the thin walls of which they draw from 

 the blood the materials of their secretion. 



XI. "Experimental Researches on the Movement of Atmo- 

 spheric Air in Tubes/' By W. D. CHOWNE, M.D. Com- 

 municated by JOHN BISHOP, Esq., F.R.S. Received June 

 14, 1855. 



In the year 1847, the author of this paper made numerous expe- 

 riments for the purpose of ascertaining what are the conditions under 

 which atmospheric air is placed with regard to motion or rest, when 

 within a vertical tube having one extremity communicating within 

 the interior of a building, and the other in the open atmosphere. 



The paper now submitted to the Royal Society contains the results 

 of investigations undertaken in the year 1853 and continued to the 

 present time, to ascertain whether the ordinary state of atmospheric 

 air contained in a vertical cylindrical tube, open at both ends, and 

 placed in the still atmosphere of a closed room, is one of rest or of 

 motion ; and if of motion, to investigate the influences of certain 

 changes in the condition of the atmosphere which either produce, 

 promote, retard, or arrest the movement. 



He demonstrates, by a series of experiments, that when a tube, 

 open at both ends, is placed in a vertical position, every precaution 

 being taken to exclude all extraneous causes of movement in the 

 surrounding atmosphere, an upward current of air is almost imme- 



