342 THE LYMPHATICS OF THE EYE, BY G. SCHWALBE. 



relations. Were the lymphatics the discharge pipes of the 

 aqueous humour, it would be clearly impossible to preserve the 

 relatively considerable pressure which exists in the anterior 

 chamber of the eye, since with the low pressure of the fluids 

 contained in the lymphatics a rapid discharge of the aqueous 

 humour would occur, which could not be compensated for 

 by the transudation of fresh fluid through the walls of the 

 vessels, and the anterior chamber would collapse. This, how- 

 ever, is avoided by the opening of the lymphatics into the 

 veins, through the intervention of the canal of Schlemm. Thus, 

 owing to the circumstance that in the small veins the pressure 

 is considerably higher than in the corresponding lymphatics, 

 and further, owing to the resistance which the fluids have to 

 overcome in their passage from the anterior chamber of the 

 eye to the canal of Schlemm, in the narrow system of fissures, 

 i,t becomes possible for the pressure in the anterior chamber of 

 the eye to be preserved at its normal height, and for the 

 entrance and discharge of fluid to be equalized. 



B. The account of the cornea in this book may be referred 

 to for a description of its canalicular system. 



c. The Lymphatics of the Conjunctiva. 



The lymphatics of the conjunctiva were discovered by F. 

 Arnold (5), and were more exactly described by Teichmann (6). 

 They arise at the margin of the cornea, where they form a 

 delicate plexus of about one millimeter in breadth ; more ex- 

 ternally they are continuous with the wide-meshed lymphatic 

 plexus of the sclerotic conjunctiva. The trunklets here soon be- 

 come stronger, and usually run in a meridianal direction, anas- 

 tomosing by means of numerous short, thin, transverse branches. 

 According to Teichmann, a few branches proceed from the close 

 plexus at the border of the cornea, in a meridianal direction 

 towards its centre, forming a zone of about 0*1 of a millimeter 

 wide. These perhaps correspond to the lymph-like structures 

 described as lymphatic by Kolliker (3), His (1), and Samisch (2). 



According to Lightbody (4), the capillaries at the margin of 

 the cornea are invested by lymphatic sheaths. I have not, 

 however, been able in any case to satisfy myself of their 

 presence. 



