48 



2. The method! of silver impregnation was first resorted to 



Fig 1. 



Injected system of channels from the cortical portion of 

 the cord. Magnified 90 dianieters. 



to decide the question whether the system of channels thus 

 injected might not possibly be lymphatics. 



The injection, however, of silver solutions, entirely failed 

 to produce the characteristic epithelial markings ; though this 

 method, as well as the simple staining of superficial sections 

 with nitrate of silver, brought into view the well-known 

 communicating stripes and spots which have been regarded, 

 in accordance with the views of Recklinghausen, as indicating 

 a system of plasmatic channels. They were, however, espe- 

 cially in the deeper layers, enormously large and very much 

 wider than those seen in other forms of connective tissue or 

 in the cornea. The resemblance of this network in size and 

 arrangement with that demonstrated by injection was so close 

 as to be unmistakable ; it remained, however, to show its 

 connection with the proper cells of the mucous tissue. 



3. The examination of unaltered sections of the cord 

 brought into view a mucous substance, traversed by delicate 

 fibrillar outlines. The fibrils were not uniformly distributed, 

 but collected into bundles, which by their divergence and 

 decussation enclosed alveolar spaces of unfibrillated mucous 

 substance. The network thus formed was not, however, com- 

 posed of closed alveoli, but rather of spaces communicating 

 freely with one another, and containing the fundamental 

 mucous substance. 



The cells of the umbilical cord are of two kinds, one 

 constant, the other extremely variable in size and shape. 

 The variable cells appear in the unfibrillated mucovis spaces 



