STRUCTURE OF LYMPHATIC GLANDS. 



193 



In the connective and allied tissues there are variously-formed 

 fissures or splits, which can be filled with fluid forced into the 

 tissues by puncturing the skin with the nozzle of a fine syringe, 

 such as is used for hypodermic injection. 



These fissures contain the protoplasmic units of the tissue, and 

 transmit the ordinary transudation stream for nourishing the tis- 



FIG. 86. 



Clefts in the Corneal Tissue of a Frog treated with nitrate of silver, which 

 leaves the spaces clear and stains the intermediate structure. These clefts 

 (a) and their processes (6) form the lymph canalicular system, and at the same 

 time are the spaces in which the corneal corpuscles reside. (Klein.) 



sues. They freely communicate one with another, and lead into 

 the beginnings of the network of lymphatic capillaries. 



The lymph capillaries run midway between the blood capilla- 

 laries, and are made up of a single layer of nucleated eudothelial 

 cells, which can be brought to light with silver staining. 



In some tissues, such as that of the central nervous system, the 

 liver and bone, the lymph vessels commence as channels encir- 

 cling the bloodvessels, or perivascular lymph spaces, as they are 



