408 QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENCE. 



result, but these are only accidental. In many cases these 

 young cells only form the entire thickness of the cisterno- 

 peritoneal wall at these points. Finally, an examination of 

 the contents of the cisterna, and some experiments on inflam- 

 mation of the peritoneum, tend to confirm the author in his 

 belief that these cavities do not communicate. 



5. On the inner Boundary Layer of Human Serous Mem- 

 branes. — Bizzozero (' Centralblatt,' 1874, No. 14) examined 

 the pleura, pericardium, and peritoneum, and in each case 

 found an extremely thin connective-tissue layer immediately 

 under the endothelium, which can often be more or less 

 easily detached as a delicate membrane. This is most easily 

 effected on the intestinal peritoneum and parietal pleura, 

 both in fresh preparations and in those which have had their 

 endothelium removed by pencilling, and then been hardened 

 in dilute spirit, potassium bichromate, or very dilute chromic 

 acid (0"01 per cent.). The isolated membrane is one to two 

 inches thick, homogeneous, finely granular, or fibrillar, con- 

 tains no cells, and swells up and becomes pale by acetic acid. 

 Its inner surface is covered by the endothelium, while its 

 outer surface rests on the wavy, felted connective-tissue 

 bundles of the serous membrane, in which there are numer- 

 ous cells. In the intestinal peritoneum it is separated by a 

 few thin connective-tissue bundles from the already known 

 reticulated elastic membrane. Both here and in the parietal 

 pleura this membrane forms an unintertmpted layer. Accord- 

 ing to the above it appears that, at least in the human pleura, 

 there can be no direct opening of lymphatic vessels into the 

 pleural cavity as described by Dybkowsky, E. Wagner, 

 Klein, and others. This structureless layer apparently cor- 

 responds to the basement membrane described by Todd and 

 Bowman, and denied or ignored by later writers. 



6. On the Lymphatic System of the Cornea. — Dr. Thin 

 ('Lancet,' 1874, p. 225), by means of impregnation with 

 silver and gold, shows that the tubes described by Bowman 

 in the cornea are lined by a layer of endothelium, which he 

 considers to be of a lymphatic nature. The endothelium 

 may be easily seen in old preparations, but may also be made 

 out in recent ones, and shows the existence of lymphatic 

 vessels in the cornea. His drawings of preparations of the 

 rabbit's cornea show large lymphatic vessels lined with a 

 distinct endothelium, and smaller vessels joining to form a 

 trunk. There are also clear spaces corresponding to the 

 lymph-canalicular system, in which the corneal corpuscles 

 are lodged. These canaliculi all communicate with each 

 other and with the lymphatics. In preparations in which 



