300 



Mr. E. E. Henderson and Prof. E. H. Starling. [Nov. 23 



the conclusion that the amount of fluid normally secreted by the ciliary 

 processes is in the rabbit about 4 c.mm. per minute. We found considerable 

 difficulties in applying this method, chiefly determined by the tendency 

 of the cannula in the vitreous to become blocked. "We therefore adopted 

 a method similar to that already employed by Niesnamoff, (7) under Leber's 

 direction. The arrangement of the experiment was as follows : — 



The hollow needle, connected by the capillary tube (containing an air 

 bubble as index) to the reservoir and manometer, was introduced into the 

 anterior Chamber. The height of the reservoir was then adjusted until the 

 bubble was stationary, showing that the intraocular pressure was exactly 

 balanced by the pressure of the fluid in the tube leading to the reservoir. 

 This intraocular pressure was of course maintained by a constant secretion 

 of intraocular fluid, exactly equal to the amount escaping by filtration through 

 the anterior angle of the eye. The animal was then killed by dividing the 

 heart. This procedure at once stopped the production of intraocular fluid. 

 The intraocular pressure, however, was maintained at its previous height by 

 the connection of the eye with the reservoir of Ringer's fluid : the escape 

 fluid by the anterior angle was therefore the same as before. The rate of 

 this escape could be determined by noting the rapidity with which the 

 air bubble moved along the capillary Uibe towards the eye, and this rate 

 must be equal to the rate of production of fluid previously obtaining in the 

 eye under normal conditions of circulation. The following table gives the 

 rate of production of intraocular fluid, determined in this way, with varying 

 intraocular pressures : — 



Animal. 



Intraocular 

 pressure in mm. 

 Hg. 



Inflow, after cessation of 



circulation, in cubic 

 millimetres per minute. 



Cat 



20 



12 



Cat 



15 



11 



Cat 



26 



12 



Cat 



2S 



10 



Cat 



14 



5 



Cat 



20 



15 



Average 



20 -5 



10 -8 



1 



It will be seen that there is a considerable difference in the case of filtra- 

 tion in various eyes, and therefore a corresponding difference in rate of 

 production of intraocular fluid, 



