454 



Messrs. L. Hill and M. Flack. 



[May 29, 



tenseness and sagged in. So it remained for some hours, until, as the fluid 

 was secreted, the tension gradually returned. In hydrocephalus we are dealing 

 with an error of metabolism ; the growth of the brain substance and the 

 secretion of the cerebro-spinal fluid are not properly balanced. The pressure 

 of the fluid and of the blood in the capillaries is the same ; it is the relative 

 secretory and growth properties of the brain and its membranes which are at 

 fault. In cases of oedema of the legs we have measured the pressure of the 

 fluid after introduction of a needle (for drainage). The pressure equalled 

 about 50 cm. of water, and rose on lifting up the leg owing to the squeezing of 

 the leg. The leg behaved, in this respect, like a bag of fluid, and the fluid and 

 capillary-venous pressure must have been the same. 



Ligation of the vense vorticosae, as shown by Adamiik, produces a very 

 large rise of intraocular pressure up to 90 mm. Hg. In albinos the local 

 hypersemia of the iris and the ciliary body can be seen. In this case, we 

 maintain, the intraocular pressure rises because the capillary -venous pressure 

 is raised almost to arterial pressure owing to the obstruction of the venous 

 outflow. The fluid contents of the eye transmit this pressure equally in all 

 directions, hence the intraocular pressure rises pari passu with the venous- 

 capillary pressure. The rise of intraocular pressure, on the other hand, is 

 ascribed by Parsons "primarily to the dilatation of the vessels, and 

 secondarily to the high capillary pressure inducing increased transudation." 

 " The anterior chamber becomes shallow and the filtration of fluid from the 

 eye is thereby at first diminished, so that increased production is accompanied 

 by diminished secretion." We find no explanation given as to how all these 

 phenomena happen in an eye bounded by a rigid capsule. We recall the 

 fact that the dead eye increases by only 7/1000 of its bulk when the intra- 

 ocular pressure is raised from 19 to 70 mm. Hg. The living eye full of blood 

 would increase much less. The shallowness of the anterior chamber is 

 clearly due to the expression of aqueous into the substance of the cornea, 

 spaces of Fontana, etc., under the influence of the high capillary-venous 

 pressure which expands the blood-vessels. 



Present day views of glaucoma are dominated by the idea that the 

 aqueous fluid is a filtration product, and that the intraocular pressure is not 

 the capillary- venous pressure but some other pressure controlled by the 

 relation of filtration to absorption. From our point of view the pathology 

 of the increased tension in acute glaucoma is plain. It is due to disordered 

 metabolism which results in a greater imbibition force on the part of the 

 disordered tissues and in arterial vaso-dilatation. Increased imbibition and 

 blood supply in one part of the eye must be compensated for by narrowing 

 of the veins and rise of vascular pressure. Hence the increased tension of 



