100 PHYSIOLOGY OF THE CIRCULATION. 



proportion between the area of the stream entering 

 the membranous tube, and that of the latter, did not 

 prevent a rapid exudation from occurring whenever 

 the height of the column in the reservoir exceeded 

 two or three inches : and the following was the only 

 method which I found effectual in obtaining constant 

 absorption, viz. to grasp the upper end of the first 

 glass tube, where it projected into the membranous 

 reservoir, so as gradually to diminish its area until 

 the stream escaping at the other end of the apparatus 

 became reduced in size to a mere thread. And so 

 long as the area of the stream entering the first 

 glass tube was in this manner limited and regulated 

 according to the height of the impelling column, 

 absorption of the external stagnant fluid surrounding 

 the membranous tube proceeded with tolerable 

 rapidity. Thus in one experiment the quantity of 

 stagnant iluid was in less than ten minutes diminished 



O 



by three ounces ; in another trial, its original quan- 

 tity of nine fluid ounces was, during the passage of 

 little more than half a pint of water through the 

 apparatus, reduced to 4 J- ounces, or one-half. The 

 stagnant fluid was occasionally coloured, and could 

 then be seen to escape with the stream issuing from 

 the syphon. At the commencement of the experi- 

 ment there was invariably some effusion, until the 

 long arm of the syphon became filled, when the pro- 

 cess of absorption began, and, if uninterrupted, would 

 gradually reduce the height of the stagnant fluid 

 from the level of the short arm of the syphon to the 

 junction of the membranous tube with the ter- 

 mination of the first glass tube. When a consider- 



